Participants were recruited to the study upon entry to the residential treatment program. Inclusion criteria were MA dependence, English proficiency, age 18 to either 45 years for men or 55 years for women , and the ability to attend exercise or health education sessions. Individuals were excluded if they exhibited medical impairment that compromised their safety as a participant, met criteria for opiate dependence, or had a psychiatric impairment that warranted hospitalization or primary treatment . On-site research staff met with interested MA-dependent participants in a study office to conduct screening and enrollment procedures. Eligible participants signed consent for study participation and completed all baseline measures. A randomized block design approach was used to assign participants to one of two study conditions: exercise intervention or health education control . Randomization to study groups was stratified by gender and severity of baseline MA use . In previous clinical outcome studies with MAdependent clients, the median number of days of use has ranged from 16–20. Therefore, we define “low severity” as using MA for 18 or fewer days in the previous month, and “high severity” as using for 19 or more days in the past month. The study’s data management center maintained the urn randomization program and the records that linked participant identification numbers to study condition. See Figure 1 Consort Diagram for study flow. The exercise intervention consisted of a progressive aerobic and resistance exercise training program that was conducted with participants three days a week during the 8-week trial .
Exercise sessions were scheduled throughout the day at convenient times for participants . Exercise sessions were about 55 minutes in length,vertical grow system structured as follows: 5-minute warm-up, 30 minutes of aerobic activity on a treadmill, 15 minutes of weight training for the major muscle groups— and a 5-minute cool-down with stretching. Specific exercise maneuvers engaged in during the weight training included chest press, front pull down, leg press, reverse lunges, calf raises, lateral raises, bicep curls, and triceps press. Each session was individual-based, guided and monitored by a study staff exercise physiologist. Using heart rate monitors, the exercise physiologist worked closely with each individual participant on training days to increase treadmill speed/slope to maintain a heart rate between 60% and 80% of maximum for 30 minutes. Once a participant was able to complete two sets of 15 repetitions of any given exercise, weight was incrementally increased. The control group consisted of structured health education sessions given to participants three days a week during the 8-week trial . Health education sessions were 55 minutes in length and consisted of various health topics, including stress reduction, health screening, healthy relationships, and sexually transmitted diseases. The sessions were scheduled at a convenient time for clients to attend and were conducted by a trained health educator in a room at the treatment facility in a “group format” . Given that the main hypothesis of this study was testing the impact of the 8-week exercise intervention on reducing mood symptoms among MA participants , the two primary outcome measures included depression and anxiety symptoms. For this, we used data collected on these measures at baseline , weekly , and at study discharge .
Participants voluntarily completed baseline measures and were compensated with $10 gift cards per session for each exercise or education session they attended, once randomized. Depression symptoms were assessed at the end of each week using the Beck Depression Inventory , a 21-item self-report questionnaire . The BDI total score ranges from 0 to 63, with scores of 0 to 13 indicating minimal depression symptoms, 14 to 19 indicating mild depression symptoms, 20 to 28 referring to moderate depression symptoms, and 29 to 63 indicating severe depression symptomatology . Anxiety symptoms were also assessed at the end of each week using the Beck Anxiety Inventory . Similar to the BDI, the BAI is a 21-item measure that assesses for symptoms of anxiety using the same total scoring and symptom range breakdown . For analyses purposes, we used the total mean weekly scores for each of the mood measures. Secondarily, we also examined the potential effects of a dose response on changes in mood symptoms, as research indicates that greater exercise adherence is associated with better mental health outcomes than less exercise adherence . For this study, dose response was measured by session adherence for both study conditions using sign-in attendance checklists throughout the 8-week trial. Hence, the total number of sessions attended was computed and scored from 1 to 24 for each participant. It should be noted that because all participants in the study were concurrently enrolled in residential treatment for MA dependence, the facility policy was drug abstinence verified by random urine drug screens conducted at least weekly during treatment. If participants tested positive, they were immediately discharged from the facility. Hence MA participants in this study were assumed to be abstinent as verified by the random drug screens used during treatment. According to treatment records, two participants, one in each group, were discharged from the treatment facility prior to study completion for positive drug tests.
These participants were not included in analyses.MA use induces complex neurobiological and physiological changes in the brain and body that are associated with numerous physical and mental impairments, including depression and anxiety symptoms . Increasingly, exercise interventions have been embraced in health care as a promising approach for populations suffering from an array of health issues . This study extends the utility of a structured exercise intervention in mitigating symptoms of depression and anxiety in a group of MA-dependent participants in residential treatment . Particular attention is given to depression and anxiety since these are problematic in early-abstinent MA users and aerobic exercise has led to improvements in such symptoms in a variety of clinical populations . Consistent with previous studies, we found evidence that an 8-week structured program of exercise produces positive effects by reducing mood-related symptoms of depression and anxiety among MA-abstinent individuals in treatment. We also found a significant dose effect on mood outcomes for the exercise condition, such that those who participated in more exercise sessions during the 8-week trial had greater symptom reduction in depression and anxiety compared to those who participated in fewer sessions. This relationship did not occur for participants in the education control group. These study findings can be useful to treatment providers interested in addressing depression and anxiety symptoms commonly exhibited among MA-dependent individuals in early abstinence. Specifically, treatment providers can encourage MA users to engage in the type of exercise used in this study to help them deal with problematic anxiety and depression symptoms that are linked to relapse and early treatment termination . The beneficial effects of the 8-week exercise intervention on reducing depression and anxiety symptoms among MA-dependent individuals in treatment should be viewed in the context of other benefits reported from previous work specific to this study. Specifically,indoor vertical garden systems we have found that the exercise intervention also has led to significant improvements in physical fitness indices such as aerobic performance and muscle strength , as well as increases in heart rate variability, a validated index of autonomic nervous system control among the MA-dependent patient sample. Future studies are needed to further explore the specific neurobiological processes that contribute to reductions in symptoms of depression and anxiety as a result of aerobic exercise. Limitations of this study should be noted. The present sample is based on a treatment involved clinical sample that participated in a RCT of an 8-week exercise intervention trial while in residential treatment; hence, findings may not be generalizable to MA-dependent individuals in other treatment settings or to those who are not seeking treatment. This study only examined anxiety and depression symptoms via self-reported BDI and BAI measures. Participants in the health education session were exposed to sessions around general health topics, including stress.
This may be limiting to the outcomes of this study since stress education may have an impact on anxiety symptoms. It should be noted that this issue is not anticipated given that the educational sessions were about stress in general and not tied to how to reduce stress specific to anxiety symptoms. Lastly, the study sample was predominately male , which reduces the generalizability of the results to both sexes. In spite of these limitations, findings in this study provide valuable information with regard to the potential benefits of exercise within a treatment population who experience dysphoric mood states. As of January 2018, in California, all individuals ages 18 and over have access to some form of marijuana . Increasing perceived approval of use and decreasing perceived risk of use coincided with an increase in daily consumption of marijuana, especially among young adults . Young adults have the highest lifetime, past year and past month prevalence of marijuana use . They also have high rates of affective disorders, including anxiety and depression . Experiencing such disorders in young adulthood can have devastating long-term consequences for the development of individuals as they may hinder or delay developmental goals associated with the transition to adulthood. Although depression and anxiety are often comorbid, they manifest differently. Whereas depression can be characterized by emotions such as despair, anger, sadness and hopelessness, anxiety can be characterized by overwhelming worry or fear. Both depression and anxiety in young adulthood can be complicated by alcohol and drug use . There is a lack of consensus as to whether marijuana plays a causal role in the development of affective disorders but marijuana does appear to increase the risk of developing symptoms of affective disorders in the long term . Yet, this contradicts individuals who report benefiting from marijuana use as it alleviates their symptoms of depression and symptoms of anxiety . However, these contradictions might be resolved by viewing individuals who use marijuana as being heterogeneous. As I argue below, the reasons why people use marijuana might inform whether marijuana improves or worsens mental health. Furthermore, gender needs to be considered when examining the association between marijuana use and mental health outcomes as depressive and anxious disorders are more common in women compare to men, whereas substance use disorders are more common in men than women . It has also been demonstrated that women experience a telescoping effect whereas they progress from initiation of marijuana use to problematic use more quickly than men do . Thus, the association between marijuana use and mental health may differ by gender. Given that marijuana use is most prevalent among young people aged 18 to 25 and that marijuana is the most widely used substance among individuals with depressive and anxious symptomatology and disorders , it is imperative to understand the associations between marijuana use and symptoms of mental health. Motives, hereby conceptualized as a cognitive explanation for a behavior , drive marijuana use. Previous work has established that motives of alcohol use are related to different patterns of alcohol use and associated outcomes . Therefore, when motives of use are not considered in the association between marijuana use and mental health or other associated outcomes, it is assumed that use behavior is the same, regardless of why an individual uses marijuana. However, as indicated in the literature on alcohol motives of use, why people use lead to different use behaviors, which are driven by different needs with potentially different associated outcomes. Furthermore, in a study of cannabis using adolescents , changes in motives of use were associated with changes in patterns of use and a reduction of problematic outcomes. This reinforces not only the notion that different motives of marijuana use engender different use behaviors but also that motives of use may be an avenue of intervention in the association between marijuana use and mental health outcomes of young adults. The literature on the topic of motives of marijuana use and mental health outcomes however fails to address certain gaps, namely: marijuana use in a context where medical marijuana is legal, validated instruments that combine both recreational and medical motives of use, gender differences in motives of use and associated mental health outcomes, and a focus on symptoms of but not diagnoses of depression and anxiety as mental health outcomes. Therefore, the purpose of this dissertation to understand the associations between motives of marijuana use and mental health among young adults who use marijuana, and to examine whether these associations vary by gender. This work will be guided by Cooper’s Motivational Model of Alcohol Use .