The last two decades have seen a worldwide liberalization of cannabis production and consumption

Participants were requested to be abstinent from MA for at least 10 days prior to testing and were required to show a negative urine toxicology for any non-prescribed substance except cannabis, as well as a negative Breathalyzer test for alcohol on the day of neurocognitive testing.MA group comparisons of neuropsychological outcomes , demographics, depressive symptoms, alcohol and cannabis use, and other lifetime substance dependence were conducted using Student’s t tests, Wilcoxon Rank Sum tests, chi-square tests, and Fisher’s exact tests as appropriate. MA group differences in neurocognitive performance were evident across domains. Given this nonspecific pattern of MA group differences, and in order to limit multiple comparisons, we present the global T scores and global impairment classifications as outcome variables in linear and logistic regression analyses, respectively. Details of domain-specific results appear in Supplementary Table 2. We first tested whether MA group differences in global functioning were attenuated by differences in estimated premorbid ability and neuropsychiatric factors by entering MA status along with performance on the Wide Range Achievement Test Reading subtest , lifetime major depressive disorder , and lifetime average daily cannabis as covariates into each model. Age, education, race/ethnicity, and sex were not considered as model covariates because they were already included in the neurocognitive test T score demographic adjustments. Next, we added lifetime average daily alcohol use and days since last alcohol use to test whether historical alcohol use,grow table controlling for recency of alcohol use, incrementally predicted global functioning independent of MA status. Finally, an interaction term between MA status and lifetime average daily alcohol use was added to examine whether lifetime alcohol use modulated MA group differences in neurocognition.

To probe interaction effects, simple slope analyses were conducted by examining the association of global functioning with lifetime average daily alcohol use within each MA group, adjusting for covariates. To avoid multicollinearity with lifetime MDD, BDI-II was not included as a covariate in initial models. Instead, BDI-II was added as a post-hoc covariate to final models in order to rule out the potential confounding influence of active depressive symptoms. To enhance interpretability of the logistic regression results predicting likelihood of global neurocognitive impairment, we present odds ratios estimated with 95% confidence intervals . All analyses were performed using JMP Pro version 12.0.1 .The present study explored how lifetime patterns of alcohol consumption, specifically a metric averaging drinks per drinking day over the lifetime, related to neuropsychological performance among MA-dependent and MA-nonusing individuals. Based on the current literature detailing the independent, adverse neurobehavioral contributions of chronic MA and alcohol consumption, it was hypothesized that the MAþ group would exhibit worse neurocognitive performance and that greater alcohol use would exacerbate the deleterious neurocognitive effects of MA use. Consistent with prior studies, we demonstrate that MAþ individuals perform worse on average across all neurocognitive domains while exhibiting modestly higher rates of neurocognitive impairment and consuming more alcohol and cannabis than their MA– counterparts. Whereas heavier drinking increased the likelihood of global neurocognitive impairment in the absence of MA dependence, no additive effects of alcohol were observed among MAþ participants. Contrary to expectations, lifetime average daily alcohol use did not predict global T scores and in fact was associated with reduced risk of global neurocognitive impairment in the MAþ group. To our knowledge, this is the first study to explore potentially modulating effects of historical patterns of alcohol consumption, as opposed to recent heavy drinking, on MA-associated neurocognitive performance. Given the known neurotoxic and neurobehavioral consequences of heavy alcohol use , these results must be interpreted with caution. However, our finding that elevated historical levels of alcohol consumption attenuate MA-related global neurocognitive impairment is consistent with prior studies demonstrating that singly addicted stimulant abusers consistently experience greater levels of neurocognitive dysfunction than those who simultaneously abuse stimulants and alcohol .

These prior findings are particularly applicable to the current investigation as both studies classified participants based on lifetime patterns of chronic stimulant and alcohol use and administered comprehensive and validated neuropsychological batteries. Although studies of the neurocognitive effects of acute, combined stimulant and alcohol use may be less generalizable to our results, some studies have reported that administration of dextroamphetamine or amphetamine sulfate following ethanol-induced intoxication in humans may dampen ethanol-related neuropsychological decrements in psychomotor performance, executive function, and working memory . Nevertheless, further research is required to determine whether acute alcohol administration following MA-induced intoxication exhibits similar neurocognitive effects and to what extent such findings can be extrapolated to chronic substance abusers. Our unanticipated results with respect to MAþ participants necessitate that we critically examine potential statistical and behavioral confounds. The significant relationship between lifetime average daily alcohol use and the dichotomous global impairment variable, as opposed to the null effect of lifetime alcohol use on continuous global T scores, reflects fundamental differences between these two measures of global neurocognition. Global T scores are computed by averaging individual T scores across the entire battery and can represent performance across the entire neurocognitive spectrum . As a result, above average performance on some measures can mask impaired performance elsewhere. Conversely, the GDS-based impairment classification accounts for the frequency and severity of deficits across the test battery with less consideration given to performance in the normal range . Figure 1 demonstrates that although average global T scores in MAþ individuals remain stable as lifetime average daily alcohol use increases, resulting in a null association, there is greater variability in performance at low levels of alcohol use, resulting in a higher percentage of MAþ individuals being classified as impaired on the GDS at low levels of use. Similarly, the MAþ group had an average global T score that only fell .35 standard deviations below the mean , yet was twice as likely to have global impairment as compared to MA– individuals, suggesting that a global index of impairment may enhance detection of the subset of MA users that are disproportionally vulnerable to MA related brain insults. Conversely, MA group comparisons on domain-specific performance illustrate the utility of T scores in detecting subtle yet significant differences that do not necessarily translate to differences in rates of impairment.

The hypothesis that neurocognitive performance attributable to MA-induced neural injury may hinder the ability to detect the relatively subtle influence of alcohol is supported by evidence that MA abuse poses greater risk for neurocognitive deficits than alcohol abuse . Although our data demonstrate an adverse, multi-domain effect of MA dependence, this effect is modest and therefore unlikely to preclude us from detecting any additional influence of alcohol use patterns. From a poly substance use perspective, the strong positive correlation between self-reported lifetime MA and alcohol use indicates that the observed relationship between greater alcohol use and lower likelihood of global neurocognitive impairment is not an artifact of heavy drinkers having less exposure to MA. Although cannabis use correlated with alcohol use, and prior evidence suggests cannabis use may attenuate MA-related neurocognitive deficits , lifetime cannabis exposure did not suppress our significant findings nor did it account for variance in neurocognitive performance. Furthermore, the negligible effects of days since last alcohol use and depressive symptoms rule out MA group differences in recent alcohol consumption and psychiatric comorbidities as a source of variance in neurocognitive performance. In a meta-analysis examining the neurocognitive effects of duration of alcohol abstinence, Stavro and colleagues found that neurocognitive dysfunction decreased following sustained abstinence for at least a year. Importantly, this meta-analysis only included patients who met criteria for alcohol use disorder and excluded patients with non-alcohol substance use disorders. Given that the present study sample included MA dependent individuals with varying levels of alcohol consumption, neurocognitive recovery facilitated by increased duration of abstinence from alcohol may be more prominent for heavier drinking populations without comorbid substance use disorders. Moreover, our study criteria excluded DSMIV-based alcohol dependence within the past year as well as evidence of long-term lifetime alcoholism. Therefore, those meeting dependence criteria would have done so only in the past and on an episodic basis. With regard to MA group differences in time since last alcohol use, these are largely explained by many MAþ participants being in recovery and abstaining from all substances currently, vertical rack whereas MA– participants may include current social drinkers. Nevertheless, days since last alcohol use did not predict our outcomes. Drawing inferences about specific biological mechanisms underlying poly substance use in humans is particularly challenging given that substance use disorders, such as MA dependence, cannot be experimentally modeled as independent factors in randomized controlled trials, and observational studies are often under powered to examine potential confounds. Although the nature of our data prevents us from empirically investigating specific biological mechanisms that may explain the interactive effects of MA status and lifetime average daily alcohol use on neurocognitive functioning, we offer several plausible neurobiological interpretations. First, the cerebrovascular abnormalities evidenced in MA use are partially attributable to the vaso constrictive properties ofMA that result in platelet aggregation . Alcohol, in contrast, is recognized to have vasodilating properties that reduce platelet aggregation . Thus, alcohol-driven attenuation of MA-induced vasoconstriction may reduce the magnitude of neurovascular dysfunction and subsequent neurobehavioral deficits experienced by MA users.

It is important to note, however, that certain studies have demonstrated a biphasic vasoregulatory effect in which alcohol’s vasodilating properties may be limited to light-to-moderate drinkers, whereas heavier drinkers are at risk for a rebound effect in which an increase in platelet aggregation is observed following acute withdrawal from alcohol . An additional source of MA-associated neurotoxicity is the induction of brain hyperthermia through increased neural activation . Brain thermotoxicity is mediated through multi-level mechanisms in which adverse cellular , local , and systemic events can contribute to neurocognitive difficulties . Despite the sensations of warmth experienced during alcohol consumption, alcohol’s vasodilatory properties result in brain and body heat dissipation that may counteract the hyperthermic consequences of MA use. Animal experiments have demonstrated that rats exposed to alcohol before and after TBI recover from TBI-induced brain hyperthermia faster and exhibit fewer deficits in spatial learning than alcohol-naïve rats . Whether such thermoregulatory benefits of alcohol, and subsequent attenuation of neurocognitive impairments, hold in the context of MA-induced hyperthermia requires further investigation. Although the neurophysiological alterations associated with increased alcohol consumption may provide neuroprotective benefits in the context of MA addiction, our data demonstrate an adverse effect of lifetime average daily alcohol use on neurocognitive function in the absence of MA dependence. Unlike the MAþ group, who on average reported heavy lifetime alcohol consumption , MA− individuals on average reported low-risk alcohol intake , 2005. Neurocognitive performance in nondrinkers, low, and moderate drinkers has been widely studied yet has yielded mixed results. Whereas many researchers posit a “j-shaped” relationship, in which light-to-moderate consumption confers neurocognitive benefits over non drinking but heavy consumption is more neurotoxic than abstinence , other studies have either found no relationship or a negative association between low-to moderate consumption and neurobehavioral outcomes . Our findings are most consistent with the latter group of studies suggesting a deleterious dose-dependent effect of alcohol consumption, even at moderate levels, on cognition and brain structure . It is important to note that despite reaching statistical significance, our findings represent a small effect size in which one extra drink per day equates to about a one-half unit decrease in global T scores. As a result, the clinical significance of this relationship may be far more relevant for heavier drinkers with borderline neurocognitive performance than higher performing drinkers. Although the present study focuses on the conditional role of alcohol in MA-related neurocognitive performance, further studies that probe the neurocognitive effect of alcohol at varying levels of consumption and model non-linear relationships are warranted regardless of MA status. Understanding limitations of the current study may guide future research to clarify the observed differential effects of alcohol use on neurocognitive functioning among MAþ and MA− individuals. Unsurprisingly, the MAþ group displayed significantly greater lifetime average daily alcohol use than the MA− group. Although the distribution of residuals from regression models were carefully examined to ensure no assumptions of normality were violated, the group difference in lifetime average daily alcohol use may impact the reliability of our MA effect estimates at high levels of consumption in which the MA– group is underrepresented. Additionally, these estimates of lifetime alcohol consumption are fully dependent on participant self-report.

Several studies have found altered prefrontal cortex processing and executive dysfunction in marijuana users

Gonzalez et al. found no differences on the BART in a sample of young adult marijuana users versus non-using controls; however, Gonzales et al. allowed for recent marijuana use , with a median of three days since past use. Because previous studies of young marijuana users allowed for recent use, the effects of residual marijuana levels may have affected task performance. In the current study, we examined risk-taking via the BART in late adolescent marijuana users with at least two weeks of abstinence from marijuana, in comparison to non-using controls. This approach considers how marijuana users function relative to their non-using peers and reduces possible residual effects from recent substance use. We hypothesized that participants reporting greater substance use would demonstrate riskier BART performance. Further, previous studies have not yet examined the relationship of risk-taking to executive functioning in adolescent marijuana users. Executive function is a complex collection of abilities primarily modulated by the prefrontal cortex.Completing the BART has also been linked to increased prefrontal cortex activation in healthy controls , and a recent meta-analysis of neuro imaging studies suggested that individuals with substance use disorders may have altered risk processing compared to healthy controls, primarily in ventromedial prefrontal cortex, orbitofrontal cortex, striatum, and other areas involved in risk and decision-making . Given the involvement of the prefrontal cortex in both risk-taking and executive functioning, we examined whether elevated risk-taking, as measured by the BART, was associated with poorer executive functioning,cannabis grow facility layout as measured by traditional neuropsychological tests. We hypothesized that a riskier approach to the BART would be associated with poorer performance on executive function tests.Participants were part of a longitudinal study of marijuana’s effects on neurocognition during adolescence and young adulthood, with assessments at intake and at 18- and 36-month follow-ups . Adolescents were recruited from local high schools.

Teens and their parents/guardians were screened for demographics, psychosocial functioning, and family history of Diagnostic and Statistical Manual for Mental Disorders, 4th Ed. , 2000 substance use and other Axis I disorders. Confidentiality was ensured within legal limits to encourage full disclosure. Prior to participation, written informed assent and consent were obtained in accordance with the University of California, San Diego Human Research Protections Program. At study intake, exclusionary criteria included history of psychiatric disorder other than substance use disorder, serious medical problem or head trauma, premature birth, prenatal drug or alcohol exposure, and substance use during monitored abstinence. Intake classification criteria for the marijuana-user group included >60 lifetime marijuana experiences; past month marijuana use; <100 lifetime uses of drugs other than marijuana, alcohol, or nicotine; and not meeting Cahalan criteria for heavy drinking status . To produce an adequate sample size, controls were included if they had <5 lifetime experiences with marijuana , no previous use of any other drug except nicotine or alcohol, and did not meet criteria for heavy drinking status. The current data were collected at the 18-month follow-up, when participants were aged 17–20 years. A total of 48 marijuana users and 52 controls completed the BART task at the 18-month follow-up; however, 24 marijuana users and 18 controls were excluded from analyses based on the following abstinence requirements: at least two weeks since last use of marijuana, other drugs, or alcohol binge ; and at least three days since last use of any alcohol or psychiatric medications . Beyond the abstinence requirements, follow-up controls were further excluded for meeting abuse or dependence criteria for alcohol or any other substance . One participant in the baseline marijuana group had no marijuana uses in the previous 18 months and was also excluded, and one additional control was excluded due to meeting DSM-IV criteria for current post-traumatic stress disorder. Following these exclusions, the resulting sample of 58 demographically matched adolescents and young adults included 24 marijuana users and 34 non-using controls. At the 18-month follow-up, marijuana users were about seven months older , and as expected, reported higher levels of marijuana, alcohol, and other drug use than controls. marijuana users had 200+ lifetime marijuana use episodes and <130 lifetime experiences with other drugs.

In addition, 10 marijuana users met DSM-IV criteria for marijuana abuse and seven for marijuana dependence , 10 met criteria for alcohol abuse, and two met criteria for other drug abuse. At the 18-month follow-up, the 34 controls had ≤15 lifetime experiences with marijuana, minimal to no previous other drug use except nicotine or alcohol .Participants were administered the Customary Drinking and Drug Use Record to evaluate their lifetime, past three-month, and past 18-month use of nicotine, alcohol, marijuana, stimulants , hallucinogens, inhalants, opiates , dissociatives , sedatives , and abuse of over-the-counter or prescription medications. Teens were also assessed for alcohol and drug withdrawal symptoms, related life problems, and DSM-IV abuse and dependence criteria . The Timeline Follow back facilitated recall of substance use over the past 28 days through a calendar layout.The BART is a computer-based risk-taking assessment . Participants used the space bar to pump 30 simulated balloons one at a time to achieve the highest possible score. Balloons pop at an unpredictable rate , and a noise follows each response . The points earned for a balloon are lost if it pops, but temporary points can be saved by choosing “Save Points.” Participants weigh the increasing risk of popping each balloon against the potential gain of continuing to pump the balloon . The primary outcome measures were the mean number of pumps for balloons that did not pop and the total number of popped balloons during the session. High values on either variable suggest greater risk taking. The number of points earned on any balloon and the total points saved are not revealed to the participant – only whether they had earned a small, medium, big, or bonus prize depending on the amount of points saved. They were shown the possible candy rewards prior to starting the task and received the reward immediately upon completion of the task. Participants had no practice trials to assess risk, and each participant completed the same task . This measure has good test-retest reliability .Participants were abstinent from marijuana, other drugs, and alcohol binge for at least two weeks prior to the assessment, verified with biweekly breathalyzer tests and urine screens including at the neuropsychological testing session.

The urine screen tested for major substances including amphetamines, barbiturates, benzodiazepines, cocaine metabolites, marijuana metabolites, and opiates. Exclusions for recent substance use are described above in the section on participants. All participants completed questionnaires and the neuropsychological battery. Teens and their parents/guardians received monetary compensation upon study completion.We used Fisher’s Exact Tests to compare categorical variables between groups and analysis of variance to examine group differences on continuous variables. Some alcohol and drug use variables did not meet requirements for parametric analysis; therefore we used the Mann-Whitney procedure to compare these characteristics between groups. Because marijuana users were slightly older than controls, age was controlled in analyses of test performance using univariate analysis of covariance . Effect sizes are presented as partial eta-squared , and interpretations of statistical significance were made if p<0.05. We used Pearson correlations to examine associations between risk-taking, demographic, and neuropsychological variables. As an exploratory analysis, we performed hierarchical multiple regressions to examine whether BART performance predicted past 18-month substance use, as described below. Distributions of substance use variables were examined and appropriately log10 transformed to meet the assumptions of parametric analysis.This study examined risk taking via the BART in late adolescents with or without a history of marijuana use. As hypothesized, participants reporting greater substance use evidenced riskier BART performance. Specifically, marijuana users with at least two weeks of abstinence from marijuana, other drugs,indoor grow shelves or alcohol binge popped more balloons than non-using controls throughout the task, especially in the first 20 balloons. Although speculative, it appears that the marijuana users started the task with a higher level of risk taking. After receiving feedback about their performance , they attempted to modify their approach to avoid popping balloons. The controls may have taken a similar approach, as illustrated in Figure 1; however, the marijuana users remained slightly more “risky” in their approach throughout the test. Notably, the groups did not significantly differ in average adjusted pumps, which is the most commonly used variable for this task. Importantly, Pleskac et al. have suggested that the average adjusted pumps score may be biased and an underestimate of risky responses because it excludes the trials in which the balloon popped, as explained further below. For this reason, the number of popped balloons may be a more sensitive measure of risk-taking. Importantly, the groups were matched on self-reported levels of depressive, anxiety, and internalizing symptoms; marijuana users scored higher on externalizing behavior, as expected.

BART performance was not associated with these self-reported mood and personality characteristics or demographic variables including age. This suggests that group differences in risk taking may be due to marijuana or other substance use, rather than other personal characteristics. Previous studies have found mixed results. Consistent with the current study, some found that alcohol and other substance use was related to riskier BART performance ; however, others did not find group differences between non-using controls and at-risk/ addicted individuals or recently abstinent marijuana users using the BART average adjusted pumps variable . Further, BART performance did not relate to cannabis use disorder symptoms in Gonzalez et al., 2012. Our study is consistent with Meda et al. and Gonzalez et al. with regard to finding no group difference on average adjusted pumps; however, the previous studies did not examine group differences in the number of popped balloons. We also found that having a riskier BART performance significantly predicted a higher number of other drug use episodes in the past 18 months, above and beyond the effects of age. The equation using popped balloons to predict past 18-month marijuana use was also significant, but higher age was a stronger predictor than popped balloons. Having a riskier BART performance did not predict recent alcohol use. In other words, it appears that BART performance was associated with other drug use but not alcohol or marijuana use when also considering age. However, that result did not remain significant when controls were removed from the analysis. The BART may therefore have had relatively low sensitivity for measuring additional risk among regular marijuana users in this sample. Future studies could explore whether BART performance is a useful predictor of additional risk above and beyond alcohol and marijuana use. In addition to elevated BART risk-taking, abstinent marijuana users performed worse than controls on one aspect of executive functioning measured, consistent with previous studies reporting deficient executive skills or abnormal brain activation among marijuana users in this and other samples . Specifically, marijuana users exhibited poorer visuomotor set-shifting relative to non-using controls. This suggests that young, abstinent marijuana users may have a mild weakness in cognitive flexibility in the context of changing task demands. Nevertheless, it is not clear if the average group difference on this task is clinically meaningful, and marijuana users did not differ from controls on other aspects of executive skills including working memory, verbal fluency, and planning. Although not correlated with putative measures of executive function, riskier BART performance was associated with faster psychomotor sequencing speed. It is possible that a faster rate of responding may produce more popped balloons, or as speculation, risky behavior without adequate forethought may result in losses. This may concur with Solowij et al. who reported that marijuana using adolescents demonstrated “reflection impulsivity,” having faster response times even when uncertain and making more errors. Vigil-Colet also found that BART performance was most strongly related to “functional impulsivity,” a style in which decisions are made quickly and impulsively under certain beneficial circumstances. On the other hand, Meda et al. used principal components analysis to show that risk-taking may be distinct from other measures of the multidimensional construct of impulsivity . Therefore the relationship between a faster processing speed, impulsivity, and risk-taking is not entirely clear and warrants additional study. Overall, the BART appears to measure distinct aspects of risk-taking that have been associated with real-world behavior , suggesting it is a useful tool for assessing risk-taking in adolescents and young adults. Since the BART was not correlated with established tests of executive functioning, this suggests that it is measuring a behavior distinct from executive function, or at least distinct from the present tests of executive functions.

Regulations have set a maximum batch size of 50 pounds of cannabis flowers

To make these cost calculations we accounted for inventory that first fails testing, but then is remediated.In addition, to understand the opportunity cost of cannabis used in the tests or lost in the process, we use data from wholesale prices and a survey of retail cannabis prices conducted by the University of California Agricultural Issues Center.Based on this information, we developed a cost per unit of cannabis tested for representative labs of three different sizes to approximate the distribution of costs in the industry.For simplicity, we assumed that testing labs of different sizes use the same inputs, but in different proportions, to provide testing services.We assume economies of scale with higher share of capital costs per unit of output for the smaller labs.We used information reported by the Bureau of Cannabis Control in the first half of 2018 to compile a list of cannabis licensed testing laboratories and distributors in California.We used information on the geographic location of testing labs relative to cannabis production and consumption to assess the cost of transporting samples from distributors to testing labs.In March 2019, there were 49 active testing licensees and 1,213 licensed distributors.Both testing licensees and distributors are located in many areas across the state, but they are concentrated in traditional cannabis production areas in the North Coast region of California and in large population centers.Table 5 shows capacities, annualized capital costs,indoor growers and other annual expenses for three size categories of testing labs: small, medium and large.The size categories are based on the number of samples analyzed annually and were chosen to represent typical firms, based on our discussions with the industry.We assume about 25% of labs are small, 25% are large and the remaining half are in the medium category.By regulation, these labs test only cannabis.

The annualized cost of specific testing equipment and other general laboratory equipment is a significant share of total annual costs.The cost of equipment and installation is about $1.5 million fora small lab, about $2.4 million for a medium lab and about $3.8 for a large lab.These costs are expressed as annual flows in table 5.Our survey and discussions with laboratories provide the rest of the estimated costs.Equipment maintenance costs, rent, utilities and labor also are large cost categories.Each of these costs is less than proportional to the number of samples tested and thus contributes to economies of scale.This cost of consumable supplies is calculated on a per sample basis and thus is proportional to the number of samples tested.Finally, the return to risk and profit is estimated as 15% of the sum of the foregoing expenditures.Our estimated total annual costs are about $1.6 million for small labs, $3.3 million for medium labs and $7.0 million for large labs.The scale advantage of larger testing labs is reflected in the testing cost per sample: $324 for large labs, compared with $562 for medium labs and $750 for small labs.These cost differences arise from economies in scale in the use of laboratory space, equipment and labor.Each large testing lab processes about 10 times the number of samples as a small lab but has annualized operating costs only about five times those of a typical small testing lab.That means that small-scale labs tend to specialize in servicing more remote cultivators or manufacturers that have products handled by smaller and more remote distributors located at a cost-prohibitive distance from large labs.We used data on the annual testing capacities of small, medium and large labs and our assumption about the number labs of each size to calculate the share of testing done by labs of each size category.We expect that small labs will test about 6% of all legal cannabis in the state by volume, medium-sized labs will test about 33% of legal cannabis, and large labs will test 61% of legal cannabis.Using these shares, the weighted average cost per sample tested is about $428.Let us now turn from the cost per batch tested to the cost per pound of cannabis marketed.

The per pound costs of laboratory testing depends on the number of pounds tested in each test.Therefore, we must consider batch size.We expect that the batch size will differ within this constraint depending on the product type and origin and size of the cultivator and manufacturer and explore implications of batch size differences.Using the weighted average cost per sample of $428, the testing cost for a small batch of 5 pounds is $85.60, while for the largest-allowed batch size of 50 pounds, the cost is just $8.56 per pound.Next, we turn to several costs not included in the cost of testing a sample in the lab.First and most straight forward is the cost of compliance with security measured including video surveillance and archival, disposal and quarantine, and other compliance costs that we estimated were equivalent to $4.88 per pound for small labs, $4.06 per pound for large labs and $3.25 per pound for large labs for a weighted average of $3.62 per pound.The cost of testing requirements on a retail cost basis is best expressed as the full cost per unit of cannabis that reaches the market.Expressing the full cost in this way raises two additional costs.The first is simple: the value of the cannabis used up in the testing procedure.Based on MAUCRSA, the sample size must be at least 0.35% of the total batch of cannabis tested.We use an average wholesale value of $1,360 per pound of cannabis flower equivalent at the testing stage, which represents a recent weighted average price across outdoor grown, greenhouse grown and indoor grown cannabis and products.Thus, for each pound of cannabis tested, flower worth $4.76 is used up.The second issue, costs associated with a failure to pass the test, is more complex.These costs include the cost of the testing process as well as the cost of the cannabis that must be destroyed when it is considered unacceptable to be marketed by virtue of a failed test.Stringent maximums for pesticides, microbials and other contamination mean that there will be a significant chance that a sample is rejected.In some cases, the owner will attempt to remediate or process that batch, intending to eliminate the cause of the non-passing the test.A batch can be remediated up to two times.If a batch fails its testing after its second remediation, regulations mandate that that batch must be destroyed in a verifiable way.This is a major cost of the testing regime required by California legislation and regulation.To estimate the cost of such rejections, we used a range of potential rejection rates, drawing from information that was available on contamination of cannabis in other states.However, the experience of other states is of limited value and must be adjusted based on information from industry sources.Washington state mandates tests on potency, moisture, foreign matter, microbiological and mycotoxin screening, residual solvent and heavy metals, but, unlike in California, testing on pesticide residues is not mandatory.Washington state enforcement is based on spot checks.Based on Washington state data, we found that in 2017, the second year after the testing began, 8% of the total samples submitted failed one or more tests.

Colorado state mandates tests on residual solvents, microbial, mycotoxins, heavy metals, pesticides and potency.The Colorado Marijuana Enforcement Division reported that during the first six months of 2018, 8.9% of total samples of adult-use cannabis failed testing.Testing on pesticide residues only became mandatory in August of 2018 in Colorado, so systematic data on test results were not available.However, the Department of Agriculture in Colorado informed us that 60% of spot-checks based on complaints or concerns between 2015 and 2017 found pesticide residues.Given the cost of cannabis that must be destroyed in case of failed tests, cultivators and manufacturers may pre-test to decrease the chances of failing official tests.For our cost analysis, we assume that 25% of cannabis is pre-tested before being submitted for the formal and binding tests.To express costs in terms of the pounds of cannabis legally marketed, and account for pretesting and pounds lost because of testing, we need to express the ratio of pounds tested to pounds that pass testing.The costs of establishing and operating a cannabis testing facility that meets California’s mandates are largely accounted for by investment in precise equipment, the cost of highly skilled labor and costs of materials.Testing is expensive, but the lost value of cannabis that fails tests to enter the legal retail market is an even bigger issue.It is difficult to predict rejection rates with great confidence; the data we present, however,vertical hydroponic system is consistent with reports of pesticide detection in California food crops and information available from other states.Evidence suggests that major drivers of both direct laboratory costs and lost cannabis costs are low or zero tolerance levels set for pesticides and the difficulty of dealing with microbial contamination.We have shown that if these low tolerance levels were applied to other California food crops, a significant proportion would have failed tests in recent years.Thus California’s safety standards for cannabis are tight compared to other states’ standards and to standards for other products within California.We note that there may be safety reasons that cannabis is subject to such tight tolerance levels, but they are not in the literature and are beyond the scope of this article.California’s system for testing cannabis has been under pressure since the implementation of the state’s testing regime in July 2018 because of difficulties in supplying the market with product that has passed the tests and has been labeled correctly.Some producers, after receiving inconsistent test results for contaminant residues from different laboratories, have voluntarily recalled product.However, California has not yet reported detailed data on official test rejection rates.Costs of testing will be reflected in the price of marketed legal cannabis.Thus it is crucial to understand the value that testing creates for consumers compared to the costs.Competition between legal cannabis and untested illegal cannabis is a major issue in cannabis policy.Rules that help ensure safe and high-quality products for consumers of legal cannabis can encourage some consumers to shift from the illegal supply chain to the legal, licensed supply chain.Before the passage of AUMA in 2016, the low prevalence of testing in California’s essentially unregulated market for medicinal cannabis indicated that many consumers entertained a limited willingness to pay for higher safety standards.

This suggests that at least some consumers may remain today in the illegal, low-priced market, even though certified, tested products are available in the licensed supply chain.Taxes and regulations will make legal cannabis more expensive than illegal cannabis.However, safety testing is the basis of product differentiation for legal cannabis sold through licensed retailers.In some agricultural product industries, growers have urged product safety and consistency standards, as well as more stringent testing standards, to increase demand.As the regulated cannabis market develops, we expect that increased access to data will help clarify the impact on demand of mandatory testing rules.PM2.5 concentrations were measured continuously, using two, co-located laser photometers , placed 80-100 cm above the floor, for five weeks in 2019.Room occupancy was not monitored.In week 1, instruments were located 30-122 cm from the sources.During week 2 and weeks 3-5, they were 6-9 and 2- 4 meters from the nearest sources, respectively.Photometers were operated with impactors to exclude particles over 2.5 µm in diameter.The photometers were zeroed once a day and calibrated gravimetrically using a controlled cigarette smoke generation system before and after each experiment.Gravimetric data from 20 cigarette smoke experiments, when plotted against the matching photometric data and forced through zero, yielded a calibration factor of 0.31 , which was was applied to the dispensary photometric data.Cannabis PM2.5 samples were also collected in the dispensary on filters for one week , and a preliminary photometer calibration factor was calculated as above.PM2.5 concentrations in outdoor air were estimated using data from an US EPA monitoring station located 2.5 km from the dispensary in an area with similar ambient pollution sources.The retail and consumption space was a single room of approximately 400 m3.Cannabis consumption occurred at three tables in one corner of the room, with sales counters located in the opposite corner.The room was served by building HVAC and by four window air conditioners that did not admit fresh air.The air conditioners had dust filters and we were unable to examine filtration in the building HVAC system.

Colorado instituted safe storage guidelines to mitigate adverse effects in children from acute cannabis intoxication

The soil that remained adhered to the roots after removal from the ground was used to produce the rhizosphere soil samples.The rhizosphere soil was removed from the roots by shaking the root into a whirlpak bag.All samples were immediately transferred to storage at 4uC for shipping back to the laboratory for processing.All root samples were rinsed with alcohol and sterile water before the extraction.DNA was isolated from 0.25 g of soil or root per extraction using standard protocol for PowerSoil DNA Isolation Kit , with the modification of heating the extraction at 65uC for 10 minutes prior to the initial vortex step.The soil physicochemical data was generated by Fruit Growers Laboratory , including total carbon and nitrogen concentrations, pH, salinity, and water content for all samples.Endorhiza, rhizosphere, and bulk soil samples for the second experiment were taken from 6 organically-grown Cannabis plants of two different strains from two locations in August, 2012: Vista and Orange County, California.Triplicate samples were taken from each of the six plants and surrounding rhizosphere , as well as from each of the two bulk soils used in the different locations , totaling 42 samples.In contrast to the first experiment, all samples were taken two weeks prior to harvest.Additionally, triplicate samples from the second experiment were taken from different roots on the same plant.Cannabinoid data was taken from the buds of three White Widow plants and one Mauie Wowie plant.All cannabinoid data was processed at Delta-9-Technologies, LLC.Otherwise, sampling procedure matched the first experiment.Recent literature has suggested a two-step selection model for the endorhiza, where bulk-soil microbial communities are filtered by increased concentration of rhizodeposits, followed by convergent host genotype-dependent selection on endophytic communities.Results from both experiments support many of the expectations produced by this model.Most importantly,dry rack cannabis the principal coordinate analysis plots for the second experiment demonstrate highly significant clustering patterns.

First, soil type is the main determinant of PC1 for the unweighted analysis of the second experiment, revealing that soil is undoubtedly the most important factor in all samples for determining what microbes are present.Second, communities within both soil types demonstrate a similar community shift from bulk soil to endorhiza samples along PC2 , which is dominated by differentiation between sample types.Specifically, endorhiza samples have high, positive values along PC2, rhizosphere samples have intermediate values, and bulk soil samples have more negative values.Third, Cannabis strain is the main determinant of PC1 for the weighted analysis of all samples in the second experiment, suggesting that convergent host genotype-dependent selection acts through controlling community structure more than composition.PCoA results exhibit how all sample types form significantly differentiated clusters in weighted analyses but that only rhizosphere and endorhiza samples form significantly differentiated clusters in unweighted analyses, suggesting niche-filtering of microbes in rhizosphere and endorhiza samples from bulk soil.Furthermore, there were no significant segregating OTUs based on unweighted analysis between cultivars in endorhiza and rhizosphere samples in the second experiment, however there were 71 when abundance was accounted for.This differs greatly from the 657 OTUs that significantly differ between soil types in the same dataset.Testing of the two-step selection model with pairwise comparisons of shared OTUs between endorhiza and bulk soil samples also validated the hypothesis that a portion of the endophytic microbes are inherited and selected from the surrounding soil, showing significantly more OTU overlap between endorhiza and their own bulk soil compared to endorhiza and foreign bulk soil.Given the results from the second experiment strongly suggesting that Cannabis cultivars have important structuring effects on both rhizosphere and endorhiza samples, it may seem troubling that results from the first experiment do not suggest this for the rhizosphere samples.However, differences in Cellvibrio abundance between experiments show that root decay could have diminished the rhizosphere effect, thus diminishing this potential signal.Sampling for the first experiment was done post-harvest, when plant tissues were undergoing senescence and decay, while samples for the second experiment were taken from actively growing plants.Considering the extensive work demonstrating the importance of plant growth stage on the microbiota, as well as the plant-soil feed backs identified in structuring below ground microbial communities, the differences between the first and second experiments are unsurprising.

The similarities, however, are surprising.In particular, that cultivar-specificity could be identified in the microbiota within the endorhiza samples in the first experiment without any input of cultivar-specific metabolites from the living plant for weeks.Although we have presented several highly significant findings supporting expectations of the two-step selection model, some expectations remain to be validated.Specifically, although the mean beta-diversity distances indicate that rhizosphere and endorhiza samples are closer than bulk soil and endorhiza samples, this difference was not significant and thus provides little evidence for the first differentiation step of the two-step selection model.Future work with the Cannabis micro-biome should focus on elucidating the role of cultivar on rhizosphere, as well as what aspects of host genotype are producing the structure observed across Cannabis strains.Increased testing of cannabinoids and decoupling this variation from edaphic factors will improve our understanding of the importance of cannabinoid production in structuring endorhiza communities.Sampling a time series of endorhiza communities across several plants may help us to understand natural variation in the endorhiza during the reproductive cycles of Cannabis.Understanding this natural variation will help direct future mechanistic studies aimed at using microbial communities to increase plant fitness, suppress disease, or augment desired metabolite production.Legalization of cannabis use is increasingly widespread across the United States, but the ramifications are unknown.In 2016 California approved Proposition 64 legalizing recreational cannabis.Unintentional pediatric ingestion is one possible ramification, as occurred in Colorado after legalization in 2009.Regional poison center cases involving marijuana increased by an average 34% per year from 2009 to 2015 in Colorado.During that time, 34% of cases involved self-reported cases of poor product storage.Children who unintentionally ingest cannabis can present with lethargy, ataxia, tachycardia, mydriasis, and hypotonia, which can lead to preventable emergency department visits, invasive workups, and hospital admissions.Despite the institution of safe storage guidelines in Colorado, a recent study found continuing sub-optimal storage practices in that state.5 This trend was mirrored in the use of medical marijuana, as oncology patients and their caregivers reported sub-optimal storage practices and had received little storage education from healthcare providers.

The 2016 California legislation did not include regulations on the safe storage and disposal of cannabis products, creating a potential for similarly unsafe storage practices.The purpose of this study, which was based on a community presenting to a pediatric ED, was to assess the prevalence of cannabis and how it is stored in the home and, secondly, to assess attitudes regarding use of cannabis and storage education among Californians who live in households with children.We conducted a cross-sectional survey with a goal enrollment of 400 adult visitors in an academic pediatric ED in California from June 8–August 16, 2018.During this time, a convenience sample between the hours of 8 am -10 pm was conducted daily in which all adult visitors were screened for eligibility and subsequently approached.The survey was generated and finalized by the investigators and research assistants based on similar studies found during literature review.The survey contained 42 yes-no or Likert-scale questions regarding cannabis use and storage, and education on cannabis storage.Eligible participants were >18 years old and lived in a household with children <18 years old.Participants were excluded if they did not speak English or Spanish, or if the patient was critically ill.Only one survey was administered per household.All participants were notified that their responses were not shared with law enforcement or their care team, and they completed the survey in the absence of a RA.English-speaking participants filled out the survey electronically and submitted their responses directly into Research Electronic Data Capture.Spanish-speaking participants filled out a Spanish-language survey on paper, which was subsequently placed in a lockbox after which these de-identified surveys were uploaded to REDCap weekly.We used descriptive statistics to analyze data.Subjects who were screened but excluded were not tracked during this study.The UC Davis Institutional Review Board approved this study.A 2017 national survey indicated that as many as 11.5% of California adults reported regular cannabis use.Of adults surveyed, 14.5% reported cannabis use in a home with children.Since the legalization of cannabis in California, there has been a steady rise in prevalence of use,7 likely due to increased availability.In our sample, users perceived cannabis to be significantly safer for both adult use and possession inside a home with children, as compared with non-users.Further study is warranted to investigate how the public perceives the risk of cannabis as more time passes since legalization.Currently, little research exists on cannabis storage in homes with children,roll bench and there is no research that describes sources of storage information.Both users and non-users strongly felt that safe storage was important despite poor compliance with safe storage practices.Our results suggest a lack of educational sources regarding safe storage despite 23 years of medical cannabis use in California.The Public Health Department of Colorado set guidelines including locking, hiding, and using child-resistant packaging, yet California does not currently define safe storage.Providing guidelines at a local or state level may provide a reference for cannabis users as well as healthcare providers.

Based on participant responses, cannabis dispensaries may also serve as another point for the distribution of safe storage information.With the increasing prevalence of cannabis use in California,downstream effects on the pediatric population should be further investigated.Healthcare providers in primary care, pediatrics, and the ED should be prepared to screen and educate families on cannabis use and the importance of safe storage in homes with children.Nonpharmaceutical interventions were developed in response to the 2009 H1N1 pandemic and included a protocol to slow the spread of future novel respiratory influenza A virus pandemics.NPIs are strategies for disease control when no pharmaceutical alternative exists and include actions at the personal, environmental, and community level.Specifically, NPIs put in place during the pandemic included travel restriction, restriction of mass gatherings and recommendations for transition to virtual events, social distancing measures and stay-athome orders, closure of non-essential work spaces and schools, and cloth face covering guidance.3,8 However, it is unclear what effect, both intended and unintended, these policy implications have on populations.It is also unclear what effect the pandemic itself has had and will have on populations.A study from the Centers for Disease Control and Prevention examined differences among stay-at-home orders across US states from March 1st to May 31st, 2020, on population movement.Stay-at-home orders were associated with decreased population movement; however, movement increased significantly as states began lifting restrictions.Kaufman et al.reported the initial effect of state variation in social distancing policies and non-essential business closures on COVID-19 rates.Social distancing and closure of non-essential businesses and public schools were shown to reduce daily COVID-19 cases by 15.4% with effects varying across states.10 Finally, Pan et al.showed that there was heterogeneity in NPI domains across the US census region and concluded that states with the most aggressive policies had the highest mitigation of COVID-19 infection.11 While heterogeneity in intensity and duration of state policies on COVID-19 mitigation were demonstrated, all such studies have been restricted to the initial wave of the pandemic and have only assessed the associations of policies on COVID-19 infection spread at the population level.The COVID-19 pandemic and policy interventions such as social distancing, closure of spaces for gathering, and stay-at-home orders may have had varying economic, health, and social effects across different populations.Of particular concern, are negative implications on lesbian, gay, bisexual, transgender, and queer and other sexual minority populations, an already vulnerable, marginalized, and stigmatized group with even larger disparities among racially marginalized communites.The COVID-19 pandemic has highlighted and exacerbated challenges for the LGBTQ community which include rising food and shelter insecurity, economic fallout, job loss, disruption in health care, elevated risk of domestic and family violence, social isolation, increased anxiety, scapegoating/discrimination/stigma, abuse of state power, and concerns about organizational survival.There is an estimated 16 million LGBTQ adults and youth in the United States of which, 5 million work in jobs that are more likely impacted due to the COVID- 19 pandemic.For instance, 15% work in restaurants, 7.5% in hospitals, 7% in K-12 education, 7% in colleges/universities, and 4% in retail, all industries that have been impacted by the pandemic.Moreover, LGBTQ communities before and during the pandemic were more likely to be unemployed, at increased risk of poverty, have issues affording health care, and experience greater workplace discrimination compared to cisgender and straight people.

Future studies should recruit a larger sample size as it will allow for greater generalizability and further analyses

Responses by managers was a common theme discussed by workers as managers have the direct ability to ban customers based on inappropriate behavior and were often the first point-of-contact for workers to report an experience of harassment.The risk of continued harassment is exasperated by apathetic management teams who were described as prioritizing customer satisfaction over workers’ safety.Workers also illustrated the unique history of cannabis as a heavily sexualized industry whose legacy continues to permeate the industry today and negatively impact worker’s experience with sexual harassment.According to interviews, workers believed that customers either could not or refused to distinguish legally operating dispensaries from trap shops where women were explicitly used as props to sell product.The lack of distinction encourages the entitlement customers feel towards exploiting cannabis workers without repercussions.Interview results presented a paradox within the cannabis industry in which legalization introduced new protections to workers while simultaneously ushering in the corporate model of the “customer is always right,” which previous studies highlight as a detriment to the ability of workers to protect themselves from threatening customers.Furthermore, regarding research question five, data indicated workers were most interested in sexual harassment-based training for all workers, managers and supervisors as well establishing and publicizing clear policies on harassment.As previously mentioned, insufficient handling of sexual harassment cases by mangers was a common theme among all interviewees, highlighting the need for their additional training.Through interviews,drying cannabis workers were able to explain, in more detail, what they would like to see covered in a sexual harassment training.Likewise, interviews provided the opportunity for workers to explain exactly what policies or guidelines they would like established and publicized in their workplace.

Examples of policies included being able to ask a security guard to walk you home, an anonymous hotline number and permission to ask security guards for assistance in closing a store for the night.Given the unique study population of this project, there are several limitations to consider when interpreting the results.As previously mentioned, the sample of survey respondents was a convenience sample of cannabis employees represented by UFCW Local 770; respondents were not randomly sampled from all cannabis retail employees in Los Angeles County.Likewise, interview participants were also recruited through snowball sampling and were not randomly selected.All workers in the study sample are represented by a labor union and therefore the generalizability of the findings to all workers in the cannabis industry is limited as rank-and-file cannabis members of UFCW represent only a small subset of the cannabis industry.And as labor unions continue to grow their membership among cannabis workers, additional studies should compare the experiences with sexual harassment among unionized and non-unionized workers.The small sample size reduced the power of the study and created challenges for isolating effect sizes between the outcomes of interest and the independent variables, particularly in the multivariate models.With the understanding that sexual harassment is an under reported phenomenon, the analyses were likely impacted by respondents who reported never experiencing sexual harassment as it is possible workers simply did not feel comfortable disclosing such information.A larger sample size of workers across the state or ideally the nation as more states legalize the consumption and commerce of cannabis may also reveal regional differences in the effects of laws and policies that protect workers’ safety.There were also several issues regarding the survey tool.Although the survey was able to gauge frequency of harassment experienced by respondents using a Likert scale, it was not conducive to creating a discrete variable of harassment and consequently incidence rate could not be calculated.For example, the response option “once a month or less” could imply harassment was experienced anywhere from two to 12 times in the last 12 months as it was the second option after reporting experiencing harassment “once” in the past 12 months.

Providing more definitive response options may aid in developing more epidemiologically accurate variables.Questions from the SEQ-DoD were also originally developed to measure sexual harassment as it is experienced by women and studies show it is not as effective for capturing the experiences of men.In order to capture more precisely the phenomena of sexual harassment by all participants, future studies should utilize a more comprehensive survey for sexual harassment.Recall bias was also present in data collection as respondents were asked to remember specific examples of sexual harassment and the frequency at which those experiences occurred in the last 12 months.Finally, without a direct comparison to another workplace or industry applying the same methodology, it is difficult to make definitive statements about prevalence of sexual harassment in cannabis relative to other industries.In 2016, when voters approved Proposition 64, they set the stage for radical change across California’s cannabis landscape.Licensed, regulated cannabis stores would soon throw open their doors.The state’s vast cannabis industry would begin to emerge from illegality, though unlicensed operations would surely persist.UC researchers immediately understood that cannabis legalization would present California with pressing new questions, along numerous dimensions, that could only be answered through rigorous, broad ranging research.How would legalized cannabis cultivation affect the state’s water, wildlife and forests? How might impaired driving, or interconnections between cannabis and tobacco, influence public health? How would tax and regulatory policy affect the rate at which cannabis cultivators abandoned the illegal market? These questions and many more are now the subject of research around the UC system, and multiple campuses are establishing centers dedicated to cannabis research.This article surveys UC’s emerging architecture for cannabis research in the legalization era — and presents a sampling of notable research projects, both completed and ongoing.

The Cannabis Research Center at UC Berkeley is an interdisciplinary program that, bringing together social, physical and natural scientists, evaluates the environmental impacts of cannabis cultivation; investigates the policy-related and regulatory dimensions of cultivation; and directly engages cannabis farmers and cannabis-growing communities.The center, according to Ted Grantham — one of three CRC co-directors and a UC Cooperative Extension assistant specialist affiliated with UC Berkeley’s Department of Environmental Science, Policy, and Management — is “focused on cannabis as an agricultural crop, grown in particular places by particular communities with unique characteristics.” For Grantham and the center’s co-founders, establishing the program was “a chance to develop policy-relevant research at the time of legalization and a time of rapidly shifting cultivation practices.” The center’s co-directors, in addition to Grantham, are Van Butsic — a UCCE assistant specialist affiliated with UC Berkeley’s Department of Environmental Science, Policy, and Management — and Eric Biber, a UC Berkeley professor of law.Other CRC researchers are associated with entities such as the UC Berkeley Department of Integrative Biology, the UC Berkeley Geography Department, the UC Merced Environmental Engineering program and The Nature Conservancy.The center itself is affiliated with the UC Berkeley Social Science Matrix.The CRC formally launched with a public event in January.The center’s ongoing research includes a multifaceted project to assess specific aspects of Northern California’s cannabis farms, including the number and size of non-compliant cultivation sites; the environmental effects of non-compliant sites ; and the challenges to regulatory compliance that cannabis cultivators encounter.According to a grant proposal associated with the research, the project is motivated by an urgent need to understand the environmental threats posed by non-compliant farms and the reasons that some farms successfully navigate state regulations while others fail.The researchers are combining high-resolution satellite images with local and state permitting data to identify permitted and non-permitted cultivation sites.In parallel, the researchers are combining permit specifications with water use models to estimate the effects on stream flows of non-permitted versus permitted cultivation.Additionally, they are determining which factors associated with cannabis cultivation are most closely linked to compliance — whether parcels are large or small, old or new — and, through written grower surveys and in-person interviews, they are seeking to understand what stands in the way of cultivator compliance.Ultimately, the work will yield a policy report outlining ways in which state and local governments can decrease the harm of non-compliant cannabis cultivation while increasing rates of compliance.The research is supported by a grant from the Campbell Foundation, provided through the Resource Legacy Fund.In another example of CRC research focused on cannabis and the environment, last year Butsic, Jennifer Carah and additional co-authors published the results of their work on “agricultural frontiers”.These are places where,ebb flow due to increased profit potential for agricultural activity, land is newly cultivated — frequently resulting in environmental impacts such as forest fragmentation and threats to sensitive species.Such transformations, the authors write, occur when economic circumstances are altered by some new mechanism — such as, in the case of cannabis, a new legal status.The researchers, documenting the emergence of such a frontier, studied cannabis cultivation sites in Humboldt and Mendocino counties from 2012 to 2016.

Using satellite imagery to develop a database of cultivation sites, the researchers correlated site characteristics such as remoteness and erosion potential with the spread of agricultural frontiers.They report that, over the study period, cannabis cultivation sites in the study area nearly doubled in number, with total acreage under cultivation likewise nearly doubling, and that a significant portion of the new cultivation occurred in areas such as sensitive watersheds.They found, for example, that nearly 90% of the areas newly developed for cannabis cultivation had been covered in natural vegetation as late as 2006.The researchers argue that agricultural frontiers can develop “almost anywhere institutions fail to prevent” them — and note that, for 18 years after medicinal cannabis use became legal in California with the 1996 Compassionate Use Act, the state devoted no funds to regulating cannabis cultivation and production.In this issue of California Agriculture, Grantham and four co-authors from the North Coast Regional Water Quality Control Board present the results of their research into cannabis cultivators’ patterns of water use in several Northern California counties.For the research that resulted in “Watering the Emerald Triangle: Irrigation sources used by cannabis cultivators in Northern California” , Grantham and his colleagues analyzed reports submitted to the board by cannabis cultivators.The researchers determined how many cultivators sourced their water from wells, surface water diversions, spring diversions and other sources; how water sourcing behavior changed over the course of a year; and how water use patterns varied according to whether growers operated within the state’s legal cannabis market.The researchers determined that cannabis growers rely on well water to a greater degree than is generally supposed — and that their reliance on well water may increase as more growers join the legal market because of well water’s less restrictive permitting requirements.In separate research, Michael Polson — a postdoctoral researcher in UC Berkeley’s Department of Environmental Science, Policy, and Management — has investigated the environmental dimensions of cannabis from an anthropological perspective.In a paper published earlier this year, Polson shows how cannabis has been identified as an environmental problem that requires public intervention.On the basis of participant observation and more than 70 interviews with subjects across the cannabis spectrum — from park rangers to environmentalists to “criminalized people” — Polson demonstrates how cannabis production has been defined as pollution — “dovetail[ing] with [cannabis] prohibition’s history of marking people and substances as socially polluting.” Polson argues, as he highlights the legacy of cannabis prohibition in environmental debates, that policy making is at its most innovative when it includes a broad range of cultivators and when stigmas are explicitly addressed.Research into the environmental aspects of cannabis is also underway at UC Davis, where Mourad Gabriel is a research associate member in UCD’s School of Veterinary Medicine.In 2018, Gabriel and co-authors, including Robert Poppenga — a professor of molecular bio-sciences at the California Animal Health and Food Safety Lab at UC Davis — published the results of their research on the effects of rodenticides on owls in northwestern California forests.The researchers, working on privately owned timberland in Humboldt and Del Norte counties, investigated the prevalence of anticoagulant rodenticides in areas characterized by illegal cannabis cultivation.Anticoagulant rodenticides, used by some cannabis cultivators to control pests, are known to affect non-target species in urban areas and recently have been shown to affect carnivores in California’s remote forest areas as well.Gabriel and his coauthors undertook to determine whether the northern spotted owl, a threatened species, is exposed to anticoagulant rodenticides in the study area — and also to determine if barred owls, a common species, can be used as a surrogate to determine exposure levels in northern spotted owls.

Cultivators and manufacturers have no reason to distinguish between the two product types

During this 13-month period, medicinal retailers continued selling cannabis to state residents with up-to-date recommendations from physicians.However, some medicinal cannabis businesses faced unusual local challenges in 2017 as some cities and counties that were opposed to the establishment of an adult-use cannabis industry restricted or banned all cannabis operations from their jurisdictions.On January 1, 2018, all cannabis businesses that had not applied for temporary licenses from state agencies became illegal from the point of view of the state.The Bureau of Cannabis Control, the California Department of Food and Agriculture, the California Department of Public Health and other state agencies propagated regulations that implemented most parts of a regulatory structure that merged AUMA with previous medicinal cannabis legislation.As of January 1, 2018, licensed distributors were required to pay a 15% state excise tax on all medicinal and adult-use cannabis sold at retail, and licensed growers were expected to pay a cultivation tax of $9.25 per ounce for any cannabis that entered legal market channels in 2018.In some counties and cities, additional local taxes were imposed.All licensees were also required to follow costly new regulations governing security, age verification, handling, labeling, child-proof packaging, inventory storage and “seed-to-sale” tracking — but not yet mandatory testing, one of the costliest elements of the new regulations.A final regulatory point worth noting is that since the launch of adult-use sales in January 2018, the California cannabis retail environment has drawn little distinction between medicinal and adult-use cannabis, and we do not distinguish between the two in our reporting of retail prices.

There are some differences between the medicinal and adult-use systems: Retailers need separate medicinal pot for growing marijuana permits to sell medicinal cannabis; the minimum age for purchasing medicinal cannabis is 18 instead of 21; the maximum quantity that may be purchased is 8 ounces instead of 1 ounce; and purchases are exempt from sales tax if the customer has a medicinal recommendation and a county-issued medicinal ID card.However, the cannabis supply for adult-use and medicinal sales is interchangeable.Medicinal and adult-use cannabis are subject to the same testing, labeling and packaging standards.In general, the only substantial cost faced by a medicinal cannabis retailer who enters the adult-use market is an additional license fee.Meanwhile, the potential market for medicinal retailers is severely limited because consumers of medicinal cannabis, if they wish their purchases to be exempt from sales tax, must obtain county identification cards for medicinal cannabis in addition to medical recommendations — at a combined cost of up to $100 per year.With adult-use cannabis now widely available, many consumers who participated in the medicinal market in 2017 chose not to renew their medicinal recommendations in 2018.From an economic perspective, the 2018 California cannabis market is thus more usefully viewed as a single market than as separate adult-use and medicinal markets.The leading source of publicly available data on U.S.cannabis retail prices is Weed maps, an internet platform that enables retailers in California and other states to publish and update their price lists, locations and other practical information on a standardized consumer-facing website and app.Weed maps has operated since 2008.Researchers have used it to study the California cannabis industry since well before the autumn of 2016, when AIC researchers first gathered information from the site.For instance, Freisthler and Gruenewald used Weed maps listings to study the industrial organization of cannabis retailers in California.Weed maps listings do not collectively represent the full California retail landscape.

We found no reliable estimates of the percentage of California retailers listed on Weed maps.But because retailers may add or remove listings from Weed maps for business or marketing reasons other than opening or closing, Weed maps provides incomplete and constantly changing coverage of California’s retail cannabis market.Bierut et al., another study that uses Weed maps data, finds that Weed maps includes about 60% of retailers in Colorado and 40% of retailers in Washington, but does not analyze California retailers on Weed maps.This uncertainty should be kept in mind when interpreting our data.We began gathering price data from Weed maps in October 2016.We recorded prices by product type and also collected information on retail sales locations and whether retailers were storefront or delivery-only operations.We collected only the minimum and maximum listed price for three of the most common cannabis products.Many retailers listed a price schedule with just two levels for each product type: entry-level and “top-shelf” prices.Some retailers maintained three to four price levels, but during the first year of data collection, we rarely encountered more than five levels.With or without intermediate prices, we had no access to information about quantities sold and could not construct quantity-weighted average prices.Moreover, cannabis strains and forms of packaging were often specific to individual retailers, and measures of specific brand or product characteristics were not consistently available on Weed maps.Considering that not all retailers list prices on Weed maps, and that some retailers who at some point listed prices on Weed maps might have removed their listings while continuing to conduct business, we supplemented our data set with prices from Leafly, a competing cannabis portal whose functionality and business model are similar to those of Weed maps.In particular, we turned to Leafly when Weed maps price information was not available for retailers whose prices we were already tracking — or, in later rounds of data collection, from retailers that had obtained licenses from the Bureau of Cannabis Control to operate in the regulated 2018 environment.Coverage provided by Weed maps and Leafly is partly overlapping: Some retailers list prices on both portals whereas others list prices only with one service or the other.To test for bias that might result from the inclusion of Leafly prices as part of our data set, we compared Weed maps and Leafly average minimum and average maximum prices in a sub-sample of non-overlapping retailers, controlling for package size, and we found no statistically significant differences between Weed maps and Leafly average minimum and average maximum prices.All retailers listed prices for one-eighth ounce of packaged flower.Not all retailers listed prices for 1 ounce of packaged flower or 500-milligram oil cartridges.

In later rounds of data collection, the share of retailers listing prices for 1 ounce of flower was smaller and the share of retailers listing prices for 500 milligrams of oil was larger.For instance, in October 2016, 90% of the 542 retailers listed prices for 1 ounce of flower and 57% listed prices for 500 milligrams of oil.In August 2017, 91% of retailers still listed prices for 1 ounce of flower and 82% listed prices for 500 milligrams of oil.By July 2018, only 49% listed prices for 1 ounce of flower and 89% listed prices for 500 milligrams of oil.The decrease in prevalence of 1-ounce packages might be associated with the introduction of regulations in January 2018 requiring that all cannabis be pre-packaged and pre-labeled, such that after January 2018, retailers might incur extra inventory risk by prepackaging cannabis in 1-ounce packages.The increase in prevalence of 500-milligram oil packages, on the other hand, might be best explained by the opening and expansion of the adult-use market.Vape pens, which are comparatively easy to use and do not require additional paraphernalia or prior experience with cannabis , may have greater appeal to “cannabis novices” than dried flower.In the interest of space, we do not list individual sample sizes for each price average in each round of data collection.During the first two weeks of October 2016, we collected prices, retailer locations and other information from each of 542 cannabis retailers on Weed maps in seven counties around California.We chose these counties to serve collectively as a reasonable approximation of the statewide market.We call this initial group of 542 retailers the “seven-county sample.” The seven counties cover a wide range of geographic and economic conditions in California.According to the U.S.Census Bureau , their basic demographics as of 2016 were in the aggregate similar to the demographics of California as a whole.The seven counties are shown in table 1.Summary statistics provided in table 1 support the notion that the demographic and economic characteristics of the sample are similar to those of California as a whole.Within the sample, the collective population is 42% Latino, 33% non-Latino white, 16% Asian and 8% black and the per capita income is about $30,600.Collectively, as of 2016, the seven counties included approximately half of the state’s population.In January 2017, March 2017 and August 2017, we collected three new rounds of prices from the seven county sample.In each of these three rounds, we collected prices from all of the retailers in the original October 2016 group that still listed price data on Weed maps or Leafly.In order to continue tracking as many of the original 542 retailers as possible, we attempted to follow businesses that moved to new locations or that temporarily closed and then re-opened.We coded retailers by county, city and phone number.When a retailer’s listing disappeared, container for growing weed we searched for other listings under the same name or phone number.When we found the same retailer or a branch of the same retail chain elsewhere in the same county, we kept the retailer in the data set.If a retailer disappeared and then reappeared in a later round of data collection, we kept it in the data set.

If a retailer removed its online price list, or moved its only location outside the original seven counties, we removed it from the data set for that data collection round.Between January 2017 and August 2017, we observed significant attrition from the initial group of 542 retailers in the October 2016 seven-county sample.By August 2017, 389 of the original 542 retailers remained in the data set.As shown in tables 2 and 3, average prices for these retailers changed little during this 11-month period.We call this “attrition” because the data collection method was consistent over this time period.In our 2018 rounds of data collection, we impose the additional condition that retailers must be licensed, thus changing the data collection method.Thus, for 2018 data collection rounds, the percentage of retailers dropping out of the data set from the original October 2016 sample of 542 retailers should not be thought of as “attrition.” Some retailers may have removed their online price lists from both Weed maps and Leafly but continued to operate.Attrition from the initial 542 retailers thus should not be interpreted solely as a measure of how many cannabis retailers left the legal cannabis segment.In January 2018, mandatory licensing laws went into effect, thus rendering illegal under state law any cannabis retailer without a temporary license from the Bureau of Cannabis Control.We verified licensing status by cross-referencing all Weed maps and Leafly listings in California with the publicly available lists of temporary licenses granted by the Bureau of Cannabis Control.If both a Weed maps and a Leafly listing were found, we used the Weed maps data and dropped the Leafly data.In computing averages for our last three data collection rounds , we calculated “legally marketed” minimum and maximum price averages at California cannabis retailers that listed prices on Weed maps and that had obtained temporary licenses to sell cannabis in compliance with state regulations at the time of each data collection round.For comparative purposes, we also collected a sample of about 90 unlicensed retailers in 20 counties from Weed maps or Leafly, distributed similarly to the licensed retailers.We chose these retailers from within a set of 20 representative counties, approximately in proportion to the relative populations of those counties.We selected retailers for this “20-county unlicensed sample” arbitrarily from the first page of search results on Weed maps for retailers in each of the 20 counties, but we did not use mathematical randomization to select the counties or the listings we chose within counties.These data may not be fully representative of legal cannabis price ranges for several reasons.First, as discussed above, not all legal retailers use Weed maps or Leafly, and prices may not be representative of all prices.The price data we collected also may not fully represent the range of products in the market, which may have varied in different rounds of data collection.As is suggested by the changing prevalence of 1-ounce flower packages and 500-milligram oil cartridge packages, product assortments may have changed within each of these categories.This problem plagues price data in many different industries, but changes in product assortments and price listings may have been especially rapid in the emerging cannabis market.

Cannabis remains one of the most popular used substances worldwide

A web-based survey that masked participants’ identity was determined to be the most suitable approach given that in-person interviews were limited by legal restrictions on UC researchers visiting cannabis farms, and mail or telephone surveys were constrained by the lack of any readily available mailing address or telephone contact information for most cannabis growers, who are understandably discrete with this information.Survey questions focused on operational features , pest and water management, labor, farm revenue and grower demographics.Two draft surveys were reviewed by a subset of cannabis growers to improve the relevance of the questions and terminology.A consistent critique was that the survey was too long and asked for too much detail, taking up to 2 hours to complete, and that such a large time commitment would significantly reduce the response.We therefore made the survey more concise by eliminating or rephrasing many detailed questions across various aspects of cannabis production.The final survey included 37 questions: 12 opened and 25 structured.Structured questions presented either a list of answer choices or a text box to fill in with a number.Open-ended questions had a text entry box with no character limit.Condensing the survey to capture more respondents resulted in less detailed data, but the overall nature of the survey remained the same — a survey to broadly characterize multiple aspects of cannabis production in California.Data from the survey has supported and contextualized research by other scientists on specific aspects of cannabis production, such as water use , permitting , law enforcement , testing requirements , crop prices and perceptions of cannabis cultivation in the broader community.Recruitment of survey participants leveraged networks of California cannabis growers who had organized themselves for various economic and political purposes.These were a combination of county,mobile vertical rack regional and large statewide organizations, with many growers affiliating with multiple groups.

We identified the organizations through online searches and social media and sent recruitment emails to their membership list-serves.The emails contained an explanation of the survey goals, a link to the survey website and a message from the grower organization that endorsed the survey and encouraged members to participate.The emails were sent in July 2018 to approximately 17,500 email addresses, although not all members of these organizations necessarily cultivated cannabis, and the organizations noted that their mailing lists somewhat overlapped the lists of other groups that we contacted.For these reasons, the survey population was certainly less than 17,500 individual cannabis growers, but because we were not able to view mailing lists nor contact growers directly, and because there are no comprehensive surveys of the number of cannabis farms in California, we could not calculate a response rate or evaluate the representativeness of the sample.Respondents were given until Aug.15, 2018, to complete the survey.All survey participants remained anonymous, and response data did not include any specific participant identifiers.Our survey, although of limited sample size, is the first known survey of California cannabis growers and provided insights into common forms of cultivation, pest and disease management, water use and labor practices.Since completing this survey, we have discussed and/or presented the survey results with representatives from multiple cannabis grower organizations, and they confirmed that the data were generally in line with production trends.Evident in the survey results, however, was the need for more data on grower cultivation practices before best management practices or natural resource stewardship goals can be developed.All growers monitored crop health, and many reported using a preventative management strategy, but we have no information on treatment thresholds used or the efficacy of particular sprays on cannabis crops.Likewise, the details of species-level pest and disease identification, natural enemy augmentation and sanitation efforts remain unclear.

Growers did not report using synthetic pesticides, which contrasts with findings from previous studies that documented a wide range of synthetic pesticide residues on cannabis.Product selection for cannabis is very limited due to a mixed regulatory environment that currently does not allow for the registration of any insecticide or fungicide for use specifically on cannabis , although growers are allowed to use products that are exempt from residue tolerance requirements, exempt from registration requirements or registered for a use that is broad enough to include cannabis.As such, it may be that in the absence of legally available chemical controls growers were choosing allowable, biologically derived products or alternative strategies such as natural enemy augmentation and sanitation.Our survey population was perhaps biased toward non-chemical pest management — the organizations we contacted for participant recruitment included some that were formed to share and promote sustainability practices.Or, it may be that respondents were reluctant to report using synthetic chemicals or products not licensed for cannabis plants.The only other published data on water application rates for cannabis cultivation in California we are aware of is from Bauer et al., who used estimates for Humboldt County of 6 gallons per day per plant for outdoor cultivation over the growing season.Grower reported estimates of cannabis water use in this survey were similar to this rate in the peak growing season , but was otherwise lower.Due to the small sample size, we cannot say that groundwater is the primary water source for most cannabis growers in California or that few use surface water diversions.However, Dillis et al.found similar results on groundwater being a major water source for cannabis growers, at least in northwest California.If the irrigation practices reported in our survey represent patterns in California cannabis cultivation, best management practices would be helpful in limiting impacts to freshwater organisms and ecosystems.For example, where groundwater pumping has timely and proximate impacts to surface waters, limiting dry season groundwater extraction by storing groundwater or surface water in the wet season may be beneficial , though this will likely require increases in storage capacity.

The recently adopted Cannabis Cultivation Policy requires a mandatory dry season forbearance period for surface water diversions, though not for groundwater pumping.Our survey results indicate that the practical constraints on adding storage may be a significant barrier for compliance with mandatory forbearance periods for many growers.More in-depth research with growers and workers is needed to explore the characteristics of the cannabis labor force and the trajectory of the cannabis labor market, especially in light of legalization.Several growers commented on experiencing labor shortages, a notable finding given that recent market analyses of the cannabis industry suggest that labor compliance costs are the most significant of all of the direct regulatory costs for growers.Higher rates of licensing compliance among medium and large farms is not surprising given the likelihood that they are better able to pay permitting costs.Yet, that the majority of respondents indicated they had not applied for a license to grow cannabis, with over half noting some income from cannabis sales, indicates potentially significant effects if these growers remain excluded from the legalization process.More research is needed to understand the socioeconomic impacts of legalization, which likely extend beyond those accounted for in the state’s economic impact analysis, which primarily focuses on economic contributions that a legalized market will bring to the state.Bodwitch et al.report that surveyed growers characterized legalization as a process that has excluded small farmers, altered local economies and given rise to illicit markets.The environmental impacts of cannabis production have received attention because of expansion into remote areas near sensitive natural habitats.The negative impacts are likely not because cannabis production is inherently detrimental to the environment, but rather due to siting decisions and cultivation practices.In the absence of regulation and best management practices based on research, it is no surprise that there have been instances of negative impacts on the environment.At the same time, many growers appear to have adopted an environmentally proactive approach to production and created networks to share and promote best management practices.Organizations that we approached to recruit survey participants had a fairly large base membership , which is on a par with other major commodity groups, like the Almond Board of California and California Association of Wine grape Growers.Membership included cannabis growers, distributors and processors as well as interested members of the public, and some people were members of more than one organization, suggesting a large, engaged community.Most of the organizations we contacted enthusiastically agreed to help us recruit growers for our survey, and we received excellent feedback on our initial survey questions.Growers who completed the survey were also clearly knowledgeable about cannabis cultivation.Some potential future research topics include the development of pest and disease monitoring programs; quantifying economic treatment thresholds; evaluating the efficacy of different biological, cultural and chemical controls; developing strategies to improve water use and irrigation efficiency; understanding grower motivations for regulatory compliance; understanding the impacts of regulation; and characterizing the competition between labor in cannabis and other agricultural crops — to name just a few.

As cannabis research and extension programs are developed, it will be critical to ensure that future surveys capture a representative sample of cannabis growers operating inside and outside the legal market,vertical grow rack to identify additional areas for research and develop best practices for the various cultivation settings in which California cannabis is grown.Approximately, 35% of high school seniors and young adults ages 19–28 reported using cannabis in the past year.Cannabis use during youth has been a recent focus in public health research, as it may influence one’s risk for reporting symptoms of anxiety and depression.A potential mechanism underlying cannabis’ influence on mood and affective symptoms may involve frontolimbic functioning.Understanding differences in frontolimbic connectivity among young adults with frequent cannabis use may provide insight into the etiology of associated mood or affective risk.Cannabinoids in cannabis, such as 1 9-tetrahydrocanabidiol and cannabidiol , are chemicals that mimic endogenous neurotransmitters anandamide and 2AG by binding to endocannabinoid receptors CB1 and CB2.THC is the main psychoactive component of cannabis and is responsible for the subjective “high” individuals experience.CB1 activity modulates the release of the neurotransmitters GABA and glutatmate.The eCB system modulates several functions related to physical and mental health, including regulation of emotional and stress responses.More specifically, the eCB system plays a role in mood and affect , integrating reward feedback , and threat related signals.Brain regions primarily involved in the affective processing system include several interacting cortical and subcortical regions.This system is highly innervated with CB1 receptors and animal models demonstrate developmental changes in CB1 expression within the mPFC, ACC and insula , suggesting the system demonstrates plasticity during adolescence.Therefore, repeated THC exposure during development may impact naturally occurring changes in eCB functioning within mesocorticolimbic regions.Indeed, daily cannabis users have shown decreased CB1 receptor density within frontolimbic regions , ACC, and insula compared to non-users which recovered after a month of abstinence.Further, acute THC administration has resulted in abnormal performance on behavioral measures of emotional processing , amygdala reactivity , and altered functional connectivity and signaling in PFC regions.However, additional research is needed to confirm the influence of repeated THC exposure on affective outcomes in adolescents and young adults.Due to the neuromodulatory role of the eCB system, examining brain functional connectivity is an important outcome to study in regular cannabis users.These relationships can be examined during tasks and also at rest, when individuals are not actively engaging in any specific cognitive tasks, called resting state, or intrinsic functional connectivity.Connectivity patterns in frontolimbic regions continue to develop into late adolescence and emerging adulthood; prefrontal maturation purports enhanced emotion regulation and behavior inhibition capabilities, giving rise to a functional coupling between frontal and limbic regions.Collectively, the developmental changes in frontolimbic connectivity are thought to enhance socioemotional regulation, specifically via functioning within the amygdala, medial PFC, vmPFC, ACC, insula, and inferior frontal gyrus.A particular region within the PFC, the ACC, also undergoes significant age-related changes in intrinsic functional connectivity, particularly in rostral ACC subregions involved in social cognition and emotion regulation.Therefore, this system may be particularly vulnerable to repeated THC exposure during development.Thus far, studies have found slower response times in users when identifying emotional faces and more liberal criterion for selecting sadness , poorer facial recognition and emotion matching , and emotion identification and discrimination impairments compared to non-users; though accuracy in emotion identification may not display a dosedependent relationship.fMRI studies have found aberrant amygdala and ACC activity in young cannabis users during affective processing tasks, including blunted ACC and amygdala activation during sub-conscious facial viewing , blunted amygdala response among youth with comorbid cannabis dependence and depression , and greater amygdala reactivity to angry faces in young adolescents.

Cannabis use also increases the perception of poor health above and beyond cigarette smoking and other relevant factors

With the majority of U.S.states having adopted legislation to medically and/or recreationally legalize cannabis, the already high prevalence of cannabis use is expected to further increase nationwide, especially among existing users.States that allow the legal use of cannabis for medicinal purposes have higher rates of cannabis use and cannabis use disorder in national survey data and specifically within the Veterans Health Administration.Veteran advocacy groups have been created to further veterans’ rights to access cannabis for medical purposes and discuss its use with their VHA providers.There are also published reports that veterans perceive cannabis to be a low-risk or safe substance unlike other drugs of abuse and expect cannabis to provide relief from symptoms of combat-related trauma.However, there has been little research on the patterns and correlates of MC use specifically among veterans.Growing research indicates that rates of cannabis use and CUD are particularly elevated among veterans with post traumatic stress disorder and major depressive disorder.These individuals are particularly likely to use cannabis as a means of coping with negative affect and with sleep disturbances.Nonveter an research also identifies cannabis use as an emotion-regulatory strategy to reduce or manage perceived aversive psychological and mood states.However, although such sleep and emotion regulation motives are commonly endorsed reasons for non-MC use among veterans in general, little is known about potential differences in motives among veterans using MC relative to those using cannabis recreationally for non-medical reasons.Motivation for MC use has been examined in non-veteran populations , with the most commonly endorsed reasons for use being pain, anxiety, and sleep problems.Besides pain management, relief of anxiety, especially PTSD, appears to be a prevalent motive for MC use in community samples and among veterans.Indeed, PTSD is now recognized as a qualifying condition by the majority of states permitting legal access to medicinal cannabis.

Sleep disturbance,grow cannabis particularly in conjunction with PTSD, is associated with more frequent and more problematic use of cannabis in non-veteran samples and with frequent cannabis use and CUD among veterans.Thus, MC use may be driven by specific motives for use that are inter-related with certain comorbid conditions that are particularly prevalent in veteran populations.Medical dispensary patients also report using cannabis as a substitute for prescription medication and for alcohol , with the most common motives for using cannabis instead of alcohol or illicit or prescription drugs being fewer perceived side effects, better symptom management , and decreased severity of withdrawal with cannabis.Indeed, the vast majority of MC patients self-report at least moderate symptom relief across all conditions.Preliminary prospective research found a 42% reduction in use of prescribed opiates over 3 months following the initiation of MC treatment.Yet, cannabis used specifically for pain management among MC users is significantly associated with past history of more severe substance use patterns including use of alcohol, illicit drugs, and non-prescribed pain relievers.In contrast to the growing literature on MC use, only a few non-veteran studies explicitly compared MC and RC users on cannabis-related behaviors and motives.MC users were found to have poorer health but lower levels of alcohol and drug use disorders relative to RC users.Compared with RC users, MC users have reported lower frequency of alcohol and drug problems during a visit to the emergency department and primary care clinic.Among MC users, patients with state legal access to cannabis had lower rates of other substance use relative to cannabis users without access to MC who might have used cannabis recreationally.To date, there has been little research on MC use in veteran populations, with only one study differentiating between MC and RC use in veterans.Findings from this online survey of veterans recruited from a pro-marijuana legalization listserv showed that MC users had more PTSD symptoms and greater combat exposure than RC veterans as well as lower levels of alcohol use.Veteran research can greatly inform federal and state cannabis-related policies, which are in constant flux yet shifting toward more tolerant practices regarding MC use within the VHA.These policies are especially relevant to returning veterans from the Operation Enduring Freedom/ Operation Iraqi Freedom/Operation New Dawn conflicts, because they have endured high stress levels due to their military experiences and post deployment reintegration problems.Like non-veteran MC users, OEF/OIF/ OND soldiers, particularly those with PTSD, also report poor general health and increased somatic symptoms such as chronic pain , greater medical services utilization , and worse sleep.

Anecdotal reports indicate returning veterans also use cannabis as a substitute for other prescribed and non-prescribed substances and may perceive cannabis to be less harmful than opioids.Therefore, both actual and perceived poor health combined with increasingly favorable attitudes toward cannabis among veterans may further increase the likelihood of OIF/OEF/OND veterans seeking MC.In summary, use of MC within the VHA is a growing clinical issue.However, there is a dearth of studies differentiating MC versus RC use patterns and correlates in veterans, despite their disproportionately higher rates of PTSD, anxiety, sleep, and chronic pain diagnoses relative to the general population.The present study has two aims.First, we describe the characteristics and motives for past year MC use in a sample of returning veterans.Second, we compare past-year MC versus RC users on socio-demographic factors and diagnostic characteristics, substance use, motives for cannabis use, and physical and mental health variables.MC use was determined by veteran self-report of using cannabis for medicinal purposes, regardless of whether a veteran possessed a medical marijuana registration card.Frequency of marijuana use was covaried in these analyses because MC users typically endorse daily or almost daily patterns of use.We hypothesized that MC veteran users would endorse more salient coping and sleep cannabis use motives relative to RC users as a means of coping with psychiatric and medical conditions.These comparisons between MC and RC users can inform the development of future VHA policy as well as current screening, assessment and clinical practices with OIF/OEF/OND veterans.To our knowledge, this is the first study to compare MC and RC users in a sample of veterans enrolled in a VHA facility.Results indicated that the most frequently endorsed conditions for MC use were anxiety, stress, PTSD,pain, depression, and insomnia.Consistent with findings from non-veteran studies, this veteran study demonstrated that MC users endorsed worse physical and mental health functioning relative to RC users.MC users were three times more likely to meet criteria for PTSD than RC users, adjusting for frequency of cannabis use, which varied across the two groups.As hypothesized, the greatest difference between MC and RC users was found for sleep as the reason for cannabis use.Furthermore, this difference remained and was one of the two significantly different motives when adjusting for frequency of use.Mental health concerns were highly prevalent in this veteran sample, in contrast to previous findings identifying pain as the most prevalent qualifying condition among non-veteran MC users.Specifically, more MC users endorsed anxiety and PTSD than chronic pain and other psychological conditions.As mentioned previously, sleep emerged as one of the most important motives for MC use, along with using for relaxation reasons and to relieve PTSD.This is consistent with other studies , indicating that sleep motives are the most robust significant mediating factor underlying the relations between both PTSD with cannabis use and increased risk of CUD.

Furthermore, MC users were more likely to meet criteria for current and lifetime diagnosis of PTSD than were RC users.One prior online survey of veterans similarly demonstrated that, relative to RC users, MC users endorsed more PTSD symptoms on a PTSD screening checklist and reported greater combat exposure and greater subjective arousal to items on the PTSD screen.These findings are not surprising given the high prevalence of PTSD among veterans using indoor cannabis grow system and with increasing number of MC users endorsing PTSD symptoms and/or history of trauma.Although controlled evidence on effectiveness of MC as PTSD treatment is currently lacking, preliminary research indicates cannabinoid receptor agonists to have beneficial effects in terms of relief from PTSD symptoms.Clearly, data from clinical trials is needed to help clarify whether cannabis helps relieve PTSD symptoms or whether it iatrogenically maintains some aspects of PTSD.Evidence in support of the endocannabinoid system’s therapeutic potential in the modulation of stress response may help stimulate the sorely lacking empirical research on the use of cannabis for psychological distress and sleep problems.Additional findings regarding MC users are worth noting, especially in the context of acquiring and using cannabis.For example, although 62% of MC users reported having a medical condition that would qualify them for a medical marijuana registration card in their state, only 24% reported having obtained one.One possible explanation for this discrepancy that we can posit from our data is that nearly 26% of MC users reported that they refrained from discussing medical cannabis with their doctor out of concern that doing so may get them into trouble and/or negatively affect their benefits and services at the U.S.Department of Veterans Affairs.Veterans also indicated they can more easily access cannabis from a source that does not require a state-issued medical card or that they obtained cannabis from someone else who had a medical marijuana card.Factors contributing to this may include prohibitive costs of maintaining a medical marijuana registration or higher prices of cannabis sold legally in dispensaries than on the black market.Future qualitative research might help explicate the nature of this incongruity.As increasing numbers of mental health care providers encounter veterans who use cannabis, many may be concerned about the risk of misuse of cannabis and other substances.

Consistent with national sample data , our findings suggest that while cannabis-related problems and CUD were more prevalent among MC users relative to RC users, none of these differences remained significant in analyses controlling for cannabis use frequency.With respect to other substance use, MC users reported lower frequency of alcohol use, as compared with RC users.This finding is consistent with other studies reporting lower alcohol problem severity and lower frequency of drug use in MC users relative to non-medical cannabis users.Groups differed specifically in terms of the frequency of alcohol consumption but were similar in terms of quantity of alcohol used once frequency of cannabis use was controlled in the analyses.Furthermore, alcohol was the only significant cannabis-use motive more frequently endorsed by RC relative to MC users in the analyses adjusted for frequency of cannabis use.Consistent with the finding on higher frequency of alcohol use, alcohol-intoxication motives reflect greater prevalence of problem alcohol use among RC as compared with MC users.Of note, while MC users reported using cannabis at least half of the time or more as a substitute for prescription medication, they did not use it as a substitute for alcohol or other drugs as often.These findings are consistent with other studies indicating significant history of past alcohol, drug and prescription substance use and misuse among MC users , with evidence from other studies suggesting cannabis is often effectively used as a harm reduction strategy to substitute for alcohol, opiates, and other drugs.For example, among Canadian medical cannabis dispensary patients, over 36% were found to report using cannabis as a substitute for illicit drugs, 41% reported using cannabis as a substitute for alcohol, and nearly 68% reported using cannabis as a substitute for prescription drugs.The most commonly endorsed reasons for substituting cannabis for the previous substances included the belief that cannabis led to less withdrawal, produced fewer side effects, and provided better symptom management.Recommendations for substance use disorder treatment providers of veterans using MC in VHA and seeking SUD treatment are limited because of the dearth of clinical trials on the impact of MC use on the effectiveness of addiction treatment combined with equivocal findings on the effect of cannabis on alcohol and drug treatment.specifically, some studies do not find negative impact of cannabis on treatment retention or compliance with opiate maintenance therapy or smoking cessation , yet cannabis has been implicated in worse outcomes in opiate and alcohol treatments.Future longitudinal studies and controlled research specifically examining the role of MC use on treatment of other SUDs is needed to help elucidate its impact on addiction treatment.Another implication of these findings is the need for more innovative treatment solutions for veterans with PTSD and sleep disturbance who may be turning to cannabis in search of relief of their symptoms.Many of the individuals with PTSD and CUD comorbidity do not have access to evidence-based integrated trauma-focused and CUD treatment.Furthermore, although MC users cited improving sleep as a central reason to use cannabis, both MC and RC users had endorsed clinically significant poor sleep quality, as measured by the PSQI, despite their use of cannabis in efforts to address insomnia and sleep disturbances.

The INCSR narrative explores a wide range of countries

Cannabis prohibition laws were initially established in the late nineteenth and early twentieth centuries through disparate national drug control initiatives.Over the course of the nineteenth century, cannabis medical uses were regulated in a patchwork manner as part of wider legal frameworks governing the production and sale of pharmaceuticals. In the US, cannabis use began to be perceived as a social problem that should be a subject of criminal regulation during the Progressive Era.This criminalization campaign was inspired by the legislative inroads made by the temperance movement during that period and by awakening nativist sentiments toward incoming Mexican migrants, whose habits of marijuana smoking became major objects of media attention and public anxiety.In 1915, California introduced the nation’s first anti-marijuana criminal prohibition. Three decades later, such prohibitions appeared in the statute books of forty-six states and a series of marijuana-related federal offenses were included in the Marijuana Tax Act of 1937.The transnational legal ordering of cannabis regulations originated during the League of Nations era.An earlier international drug convention, signed at The Hague in 1912, focused on regulating opium, morphine, and cocaine and did not include implementation mechanisms. Under the League’s auspices, new requirements concerning the regulation of medical and non-medical uses of cannabis were introduced at the 1925 International Opium Convention. However, the pre-UN frameworks of international drug control did not place emphasis on the use of punitive measures to regulate cannabis or other psychoactive substances. Although the US had strongly advocated the introduction of a strict prohibitionist approach, this position was met with resistance from European colonial powers that had significant financial interests in the production of opium and coca and the manufacturing of their derivatives.

In the absence of an international consensus regarding the need to strengthen the criminal regulation of illicit drug use,vertical grow system the preUN drug control framework focused on the development of administrative measures to govern cross-border commodity flows and to encourage a more effective domestic regulation of local drug markets.Following WWII, the growing capacity of the US to shape the rules and institutions of the international drug control system facilitated the move of the prohibitionist approach from the periphery to the center of the policy agenda.To a considerable extent, the institutionalization of the cannabis prohibition TLO provides a paradigmatic example of what has been usefully conceptualized as “globalized localism”—a process by which policy models that originated in the distinctive cultural and institutional contexts of a powerful country come to be perceived as global standards due to their inclusion in treaties, diagnostic indicators, interpretive guidelines, and other instruments of transnational legal diffusion. The introduction of the Single Convention on Narcotic Drugs in 1961 served as an important milestone in this process.The Convention frames the issue of drug use as a moral problem, stating in its preamble that “addiction to narcotic drugs constitutes a serious evil for the individual and is fraught with social and economic danger to mankind.” In line with this moralizing framing, the Convention requires signatory countries to criminalize a wide range of drug-related activities. Responding to the increasing production and use of synthetic drugs as part of the rise of the counter-cultural movements of the late 1960s, the 1971 Psychotropic Drug Treaty applied these policy principles to synthetic psychoactive drugs, such as opioids and amphetamine-type stimulants. The 1988 Convention against Illicit Traffic in Narcotic Drugs and Psychotropic Substances further expanded the array of criminal justice enforcement measures states are required to adopt. Importantly, however, the mandatory criminalization norms established by the UN drug conventions are defined in a manner that leaves two major sources of textual ambiguity regarding their scope of application.

First, the conventions deliberately refrain from providing a definition of what constitutes medical and scientific uses of drugs. Second, they clarify that countries should implement the duty to criminalize drug-related activities in accordance with their domestic constitutional principles. As is often the case, these two provisions are products of efforts to paper over divergent policy preferences. During the negotiations of the Single Convention, several countries objected to banning certain drugs that have traditional and quasi-medical uses among indigenous populations. India, for example, expressed concerns regarding the implied need to criminalize traditional uses of bhang, which is made from cannabis leaves with a low Tetrahydrocannabinol content. Other countries emphasized the need to retain interpretive flexibility in light of the possibility that future research would reveal new medical benefits. The resulting compromise encouraged countries that would not have otherwise supported the prohibitionist principles set by the treaties to come on board. However, this compromise also sowed the seeds of later controversies regarding the ways in which cannabis prohibition norms should be applied. As the following discussion shows, these controversies will set recursive processes of transnational legal change in motion, leading to the settling and unsettling of specific interpretations of the scope and meaning of these norms.It is an irony of history that the first decade following the entry into force of the Single Convention experienced a marked increase in the prevalence of cannabis use in Western countries. When the Single Convention was signed in 1961, cannabis use was particularly prevalent in developing countries where the plant was traditionally cultivated, while it had little impact on mainstream culture in North America and Europe. By the end of the decade, the drug acquired unprecedented political salience not only in light of objective increases in the prevalence of its use but also due to its symbolic association with emerging countercultures and the perceived threat they putatively posed to public morality. These dramatic changes intensified the enforcement of cannabis offenses, but they also attracted heightened public attention to the negative consequences of such enforcement efforts.

In the late 1960s, there was an historical increase in the rates of arrests, prosecutions, and convictions of cannabis users in various Western countries. The magnitude of this change was most remarkable in the US. In California, for example, the number of people arrested for marijuana offenses increased from about 5,000 in 1960 to 37,514 in 1967.Arrests for cannabis possession became increasingly common in countries such as Germany, the Netherlands, and Canada as well.The civil rights implications of these increased levels of drug law enforcement generated vigorous public debate on the justifications of treating cannabis on par with other psychoactive substances that are widely perceived to be more dangerous and harmful.Disagreements regarding whether cannabis should be classified under the strictest schedules of the UN drug control treaties were already evident during the Plenipotentiary Conference, which drafted the Single Convention.However, it was only as a result of the increased enforcement of cannabis prohibitions that such disagreements precipitated domestic forms of political and legal resistance. Due to increasing public criticism, national governments in several countries appointed public committees to consider the effectiveness of the existing laws. These committees directed strong criticism towards the criminological and medical underpinnings of the prohibitionist approach and sided with proponents of the decriminalization of mild forms of cannabis use. President Nixon’s famous identification of drug abuse as “America’s public enemy number one” led to the nomination of the National Commission on Marihuana and Drug Abuse . To the surprise of many, the Commission’s 1972 Report, entitled Marihuana: A Signal of Misunderstanding, concurred with the liberal approach endorsed by other national investigation committees. While the Commission emphasized that cannabis was not a harmless substance, it stressed that its dangers had often been overstated. It advocated repealing the criminal prohibitions on the possession of small amounts of marijuana and establishing alternative measures to address the public health concerns associated with cannabis use. Such reforms, the Commission stated,mobile grow systems are needed to relieve “the law enforcement community of the responsibility for enforcing a law of questionable utility, and one which they cannot fully enforce.”These recommendations were repudiated by the Nixon administration, but they inspired grassroots activists to mobilize cannabis liberalization reforms at the state and local levels. In 1973, Oregon became the first state that decriminalized the possession of small amounts of marijuana. Eleven states followed suit during the next half of the decade.The failure of the US national administration to secure the compliance of state governments with the prohibitionist norms it sought to propagate internationally provided a clear indication of the decline of the cannabis prohibition TLO. However, rather than precipitating the global circulation of new models of cannabis-liberalization reform, this early crisis stimulated new cycles of recursive transnational lawmaking, leading to the entrenchment of the prohibitionist approach. In the US, calls to reintroduce tougher drug laws resonated with the wider conservative offensive against the putative “soft on crime” inclinations of liberal policymakers in the post-civil rights era.Opponents of legalization sought to challenge the public health frame that gained increasing influence in the wake of the Shafer Commission’s Report and to contextualize the issue of cannabis use as yet another symptom of a putative law and order crisis in American cities.

The proliferation of grassroots parents’ movements lobbying for the stricter regulation of marijuana provided considerable political momentum for the introduction of tougher penalties for trafficking and possession offenses.The process by which cannabis prohibition norms again became settled at the national level in the US provided facilitative conditions for the increasing involvement of the federal government in exporting its drug policies to other countries. This effort became increasingly consequential in an historical moment in which the US came to perceive itself “not just as a powerful state operating in a world of anarchy” but as “a producer of world order.”With the end of the Cold War, new discourses of “securitization” emerged as part of the search for a new way of grounding America’s internationalist engagement.Drug policy became increasingly aligned with national security issues pertaining to the activities of insurgent and terrorist groups in Latin American countries and to the risks posed by these groups to the democratic stability and peace in the region.This new frame of diagnosing the implications of the illegal drug trade led to the development of new modes of defining the goals of US counternarcotic policies as well as the strategies through which such goals should be pursued. These new strategies have sought to reduce drug production at the source, to combat drug trafficking en route to US borders, to dismantle international illicit drug networks, to reduce drug demand at home and abroad, and to incentivize foreign governments to cooperate with US counternarcotic goals. The institutionalization of these strategies necessitated strengthening the capacity of the US government to influence the drug policies of other countries and to dominate the transnational agenda of cannabis control. From the mid-1980s onwards, the US government institutionalized an array of multilateral, bilateral, and unilateral measures intended to coerce, induce, and socialize other countries to cooperate with its counternarcotic strategies.Its multilateral efforts have largely been based on the extensive funding and support of international and regional organizations that are committed to the prohibitionist approach. In this context, the US has consistently pushed for an expansion of the International Narcotic Control Board’s monitoring authority and has served as a staunchest defender of its prohibitionist policies.Building on and expanding the scope of the international obligations enshrined in the Vienna Convention and the INCB recommendations, the US has made extensive use of bilateral treaties to create an issue-linkage between states’ willingness to adopt zero-tolerance models of drug policy and their eligibility for foreign aid. Over the next decades, such bilateral agreements provided a basis for the operation of extensive cooperation and capacity-building projects in countries as diverse as Afghanistan, Colombia, Mexico, Nigeria, Peru, Ghana, Thailand, and many others. Along with these multilateral and bilateral instruments used to influence the drug policies of other countries, the US government has had an extensive reliance on unilateral tools of imposing economic and reputational sanctions on non-compliant states. In 1986, Congress introduced the Omnibus Drug Enforcement, Education, and Control Act, which created a certification process for drug-producing and drug-transit countries.The certification process requires the president to withdraw financial assistance and support in multilateral lending institutions from countries that fail to comply with requisite benchmarks of anti-drug policy. To enable congressional deliberations over such sanctions, the US Department of State submits an annual International Narcotic Control Strategy Report that identifies the major illicit drug-producing and drug-transit countries and evaluates the extent to which their domestic policies are in compliance with the US counternarcotic agenda.

Cannabis use has also been associated with abuse of other illicit substances

According to the NASEM report, there is a moderate level of evidence of a statistical association between cannabis use and the development of substance dependence and/or substance abuse disorder for alcohol, tobacco, and illicit drugs.Multiple cohort studies have demonstrated these results.Four separate discordant twin studies have found that the twin who used marijuana was more likely to use other substances even after controlling for environmental and genetic influences.Although some studies reported that medical cannabis has resulted in improvements in opiate-related deaths,Colorado has had an increase in poisoning and deaths from opiates and methamphetamines since 2010, with the highest in 2017. These rates have increased nationwide as well and the influence of cannabis in Colorado is difficult to discern. Nevertheless, the increase in overdose deaths in Colorado is alarming. These data are shown in Figure 6.25 Although animal studies do not consistently translate to human effects, rat studies can provide some mechanistic clues. After exposure to tetrahydrocannabinol , rats have an increased behavioral sensitization response to not only THC but also opiates and nicotine.Studies also demonstrate that these behavioral changes in rats correspond to neuronal activity changes in mesolimbic dopamine neurons in the ventral tegmental area and nucleus accumbens and that cross tolerance results with exposure to morphine, amphetamines, and cocaine.Repeat morphine self-administration has been shown to be significantly lower in CB1 knockout mice and opiate withdrawal symptoms significantly less when the knockout mice are administered naloxone.The effect of cannabinoids on the cardiovascular system is complex and an area of ongoing research.

Of concern to practicing emergency physicians is ST-segment elevation myocardial infarctions and acute stroke presentations with a close temporal relationship with cannabis grow racks use, which have been documented in multiple case reports in otherwise young, healthy, male patients.The NASEM summary found there was a limited level of evidence of a statistical association between acute cannabis use and triggering an acute myocardial infarction , ischemic stroke, or subarachnoid hemorrhage.The WHO review states: “There is evidence that cannabis use can trigger coronary events. Recent case reports and case series suggest that cannabis smoking may increase cardiovascular disease risk in younger cannabis smokers who are otherwise at relatively low risk.”6 CDPHE found moderate evidence that marijuana use increases risk of ischemic stroke in individuals younger than 55 years of age and limited evidence that acute marijuana use increases risk of myocardial infarction.The main case crossover study cited for the AMI findings demonstrated that the risk for AMI associated with cannabis use during the hour preceding symptoms of AMI was elevated 4.8 times over baseline . This risk was substantially reduced following that hour.A review of nationwide inpatient sample data from 2010 to 2014 demonstrated a 32% increase in inpatient admissions for primary diagnosis of myocardial infarction and secondary diagnosis of cannabis use disorder . The overall mean age of patients was 41 years old. These patients also had longer lengths of stay, higher hospitalization costs, and higher levels of morbidity due to AMI following hospitalization than non-cannabis users.84 In a study reviewing secondhand marijuana smoke exposure, the authors found that one minute of exposure substantially impaired endothelial function in rats for at least 90 minutes, considerably longer than comparable impairment by tobacco secondhand smoke.The pathophysiological basis of these events is not fully understood and a full discussion is beyond the scope of this review. In short summary, it may encompass a complex interaction between exogenous cannabinoids and the endocannabinoid system, autonomic nervous system, oxidative stress, direct cellular effects on the endothelium, and pro-coagulant effects.Exposure to THC causes activation of the sympathetic nervous system and inhibition of the parasympathetic nervous system.These effects include elevated heart rate, serum norepinephrine levels, elevated supine blood pressure, and increases in left ventricular systolic function.Smoking results in decreasing oxygen delivery to the heart and other vital organs and may be further compromised by increasing carboxyhemoglobin levels.

The impaired myocardial oxygen demand-to-supply ratio following cannabis smoking has been shown to reduce the time to onset of symptoms during exercise in patients with stable angina.Direct effects of cannabis on blood vessels are complex due to the differing compounds in cannabis and the functional properties of the blood vessels examined.Studies are inconsistent regarding the effects on vasoconstriction and dilation. Cannabis has been consistently shown to produce vasodilation with resultant orthostatic hypotension,but it has also been implicated in vasoconstrictive arteritis mechanisms.A large review article suggested that there are three phases in cardiovascular parameters affected by the endocannabinoid system and that different chemical constituents of the cannabis plant have varying effects at different target organs, which may account for the differences.Transient vasospasm and reduction in cerebral blood flow are well described and may underlie changes in coronary, cerebral, and peripheral arterial systems leading to end organ ischemia.Myocardial blood flow has been shown to correlate inversely with circulating plasma levels of endocannabinoids.Cannabis has also been shown to be a potent source of cellular oxidative stress through formation of reactive oxygen species, and this may contribute to endothelial dysfunction and promote regional arterial vasospasm.THC has also recently shown a dose-dependent procoagulant effect.This ex vivo observation has been supported by reports of thrombotic coronary artery occlusion in young individuals without underlying atherosclerosis.There are also cannabinoid receptors on the surface of platelets and THC has been shown to increase the surface expression of glycoprotein IIb–IIIa and P select in in a concentration-dependent manner resulting in platelet activation.Figure 7 summarizes these effects.Varying cultivation techniques and end-product alterations further complicate the understanding of the physiological effects of cannabis. Cannabis plants can be altered to achieve higher growth rates, changes in potency, and increased bud production. These techniques can include use of varying soil types, fertilizers, and pesticides that can result in physiological effects. These changes may also result in exposures to possible fungal agents such as powdery mildew and botrytis; budworm or mite infestations have been reported in the literature. Historically, there have been reports of bacterial contamination with salmonella, enterobacter, streptococcus, and klebsiella, as well as case reports of fungal spore contaminants, including mycotoxin‐ producing strains of aspergillus.There are three pathways through which cannabis may be contaminated with heavy metal substances.

Firstly, cannabis is able to remove heavy metals from substrate soils and deposit these in its tissues by virtue of its bio-accumulative capacity. Secondly, cross‐contamination may occur during processing . Thirdly, post‐processing adulteration may occur, whereby metals may be added to the preparation to increase weight and thereby appreciate its street value. There are case reports of lead and arsenic poisoning from cannabis.Pesticides are also commonly used in cannabis cultivation. In a report from Washington State, laboratory analysis revealed that 84.6% of legalized cannabis products contained significant quantities of pesticides including insecticides, fungicides, miticides, and herbicides. These comprised a wide array of different substances and encompassed proven carcinogens , endocrine disruptors, as well as a variety of developmental, reproductive, and neurological toxins.There are also changes in end-product concentrations through post-processing of the plant. These changes include creation of oils, waxes/shatter, and dabs. Oils are created by removing the hydrophobic components such as THC with a heated butane solvent. THC concentrations may reach up to 55.7%.Waxes and shatter are concentrated and solidified oil with THC concentration reaching up to 90% THC.Dabs are composed of heated wax and are inhaled off of an object such as a nail, which even further concentrates THC content over 90%.Preparation of these concentrated products has also led to fires and explosion injuries in amateur production attempts in garages, tool sheds, and vacant homes.In Colorado 29 patients with butane hash-oil burns were admitted to the University of Colorado Burn Center from 2008-2014. Zero cases presented prior to medical liberalization, 19 during medical liberalization , and 12 from January–June 2014 at the study’s conclusion. The median total body surface area burn size was 10% . Median length of hospital admission was 10 days. Six required intubation for airway protection while 19 required skin grafting.Marijuana shop employees not trained in medicine or pharmacology are giving medical advice that may be harmful to patients. A recent study in Colorado found that employees are giving medical advice 70% of the time to use cannabis for treatment of nausea and vomiting in pregnancy and few dispensaries encouraged discussion with a healthcare provider without prompting.The author has personally had patients bring in products recommended by dispensary workers with a recommended potency and frequency of use and report being advised to stop their usual medications and use the cannabis product instead.

Cannabis dispensaries provide medical advice and offer treatment without medical training even when this may harm the patient.There are potential therapeutic intervention targets for cannabinoids. In general, these therapeutic targets require a high ratio of cannabidiol compounds , and are from products that significantly differ from those found in commercial dispensaries. The NASEM report found substantial evidence that cannabis grow system or cannabinoids are effective for the treatment of chronic pain in adults, as an antiemetic for chemotherapy-induced nausea and vomiting, and for improving patient-reported multiple sclerosis spasticity symptoms. They also found moderate evidence that cannabis or cannabinoids are effective for improving short-term sleep outcomes associated with obstructive sleep apnea, fibromyalgia, chronic pain, and multiple sclerosis.Studies have also demonstrated that cannabinoids may improve cardiovascular outcomes.92,117 Likely the most significant treatment implication has been in patients with refractory epilepsy, most commonly in patients with Dravet’s syndrome and Lennox-Gestault syndrome, but also in other patients. This has led to the U.S. Food and Drug Administration approving Epidiolex in June 2018 for the treatment of Dravet’s syndrome and Lennox-Gestault syndrome.Despite these potential medicinal uses, current Colorado legal distribution of cannabis products goes through an intermediary bud tender before making it to the patient which may not consistently promote therapeutic benefit; there is insufficient training of dispensary staff to serve this purpose.The potential positive health effects of cannabis rest on which of the multiple species and hybrids are studied and their specific chemical composition. One of the difficulties in determining the physiological effects of cannabis is that “marijuana,” or “cannabis,” can refer to multiple species of plants with widely varying chemical compounds and corresponding variable physiological effects. The cannabis genus includes multiple species, most commonly Cannabis sativa and Cannabis indica, and within those are hybrids specifically developed by growers to achieve a specific effect. For example, the commonly used term, hemp, refers to a variety of Cannabis sativa that is fast growing and can be spun into usable fiber for paper, textiles, clothing, bio-fuel, animal feed, and other industrial uses. Hemp has low concentrations of THC and higher concentrations of CBD. The differences in composition offer different potential treatment effects. For example, the effect for pain control cited in the NASEM review was primarily found with nabiximols , a cannabis extract mouth spray that delivers a dose of 2.7 mg of THC and 2.5 mg of CBD.For comparison, a typical marijuana cigarette or joint contains 0.5 g of marijuana and THC content ranges from 12-23%; therefore, a typical joint contains 60-115 mg of THC, 20-40 times the medicinal dose. The NASEM cautioned that many of the cannabis products sold in state regulated markets bear little resemblance to those available for research at the federal level in the U.S.This is further complicated in that commonly sold cannabis products are often mislabeled for CBD and THC content. One study showed only 17% of dispensary products were accurately labeled.Scientific studies, particularly for treatment of pain, have been limited by a substantial bias, and results have varied.Some demonstrate improvement in pain10 with coinciding decreases in opiate abuse,while others show the opposite.The conflict between federal and state laws on the medical use of cannabis products, the lack of consistency among state laws, and the availability of artisanal products in dispensaries, with high variability between composition of products, have caused significant confusion for researchers and limited the ability to fully and accurately research the true effects of commonly available dispensary cannabis products.This was not a systematic review of the literature but rather a summary of selected research including several large reviews from the NASEM, the WHO, and the CDPHE. There is undoubtedly much literature, some of it conflicting, not cited here. However, as other states and countries wrestle with decriminalization and legalization of cannabis for personal use and sale, it is crucial to report the Colorado experience as a cautionary tale. This review summarizes a large body of research for practicing emergency physicians who are increasingly confronted with questions and patients who use cannabis.