In some countries, such as Spain, only cannabinoid-based preparations are approved for select diseases , while other countries, such as Germany or UK, have established a more liberal approach, which allows physicians to prescribe unprocessed herbal cannabis for certain illnesses. Based on a growing body of evidence supporting the therapeutic potential of cannabis, the World Health Organization recommended that cannabis should be rescheduled in order to facilitate medicinal regulations in member states. With some delays, the rescheduling was carried out in December 2020 by the United Nations Commission on Narcotic Drugs. It is now reasonable to expect more European countries to follow this decision and legalise unprocessed herbal cannabis for medical purposes. Moreover, in light of the liberalisation of cannabis policy in North America, the option of recreational legalisation is broadly discussed in many European countries . In fact, Luxembourg announced a decision to legalize the sale of cannabis for recreational use in 2019. In the same year, the Netherlands passed a controlled cannabis supply experiment bill which will evaluate the impact of legalising the supply of cannabis for recreational use in an experimental design. Lastly, legislative changes towards decriminalization have been implemented in 2001 in Portugal and more recently in Czechia. In order to provide a strong empirical framework for assessing the health effects of changes in cannabis policy in Europe,trimming tray weed rigorous public health monitoring of cannabis in Europe is crucial.
Currently, public health monitoring of adult cannabis use is carried out by two international bodies that routinely collect and publish data on several cannabis indicators, including prevalence of use, treatment rates, and potency levels. First, the United Nation Office on Drugs and Crime collects annual data on prevalence of illegal drug use as well as further drug-related indicators from all UN member states . In their annual “World Drug Reports”, these data are summarized at the regional as well as global level. Second, the European Monitoring Centre for Drugs and Drug Addiction the responsible body for monitoring illegal drug use and drug addiction in Europe compiles a number of cannabis related indicators, which also serve as base for the annual European Drug Reports. In addition to these two agencies collecting empirical data on cannabis, the GBD study routinely estimates the prevalence of CUD for all countries. In the current contribution, we extracted and analysed cannabis indicator data from publicly available sources, including prevalence of use, prevalence of cannabis use disorder , treatment rates, and potency of cannabis products in Europe. We aimed to describe the trends of these indicators for the period 2010 to 2019 and the possible public health implications. Further, we aimed to highlight limitations in the available data, in order to identify the steps required to improve current practice in monitoring of cannabis use and harm in Europe.The treatment demand indicator reflects information about the number and the profile of people who enter treatment for drug problems each year. A uniform protocol guides EMCDDA member states to collect the required data in a comparable way across all countries. For the formal TDI definition and further methodological details, see Supplemental Material 1. For interpreting TDI data, variations in coverage of treatment entries between countries and over time need to be taken into consideration. We attempted to consider differences in coverage of TDI data, i.e., the share of all relevant treatment units covered by the indicator, between country and over time.
However, a complete assessment of TDI coverage is not available but the most recent report for the year 2014 marks substantial cross-country differences in the TDI coverage rates from 60% to 100% for out-patient treatment centers and from 30% to 100% for in-patient treatment centers. To further elaborate on TDI coverage variations, we examined how the number of treatment units covered by the TDI differs between countries and developed over time .EMCDDA member states monitor and report cannabis potency according to the total concentration of delta-9-tetrahydrocannabinol in sample weight, to the nearest 0¢1%. For the current analyses, we obtained the median THC levels in herbal cannabis and resin. In contrast to survey and TDI data, the EMCDDA does not disclose any details on the underlying sources of THC data per country and year. While the THC data aim to be representative of the retail level, the agency acknowledges several methodological limitations that might render some data not representative. It can be assumed that the presented data are predominantly obtained from a sample of police seizures of cannabis. For Germany, THC data were corrected and completed by the respective EMCDDA focal point.We reviewed UNODC data but could not identify any cannabis-related indicators relevant for public health monitoring that are not already captured by the EMCDDA data collection. In fact, both agencies collect data on prevalence of use and on treatment rates. However, we chose to refer to EMCDDA data for the following reasons: the UNODC ‘general population’ prevalence database does not include information on the age range of the target population or exact references. Further, it contains several estimates derived from the school survey initiative ESPAD, which should not be reported as general population estimates.
As for TDI, we compared data from UNODC and EMCDDA for 2017 for 16 countries with data available in both data bases. For any drug treatment, data were only consistent in half of the countries. Further, treatment demand for CUD was only reported as percentage of all treatment demand in the UNODC data base, requiring recalculations and additional assumptions to report CUD treatment rates. Based on this assessment, we restricted our analyses to data provided by the EMCDDA.Data on CUD prevalence including uncertainty intervals by 5-year age bands were retrieved from the GBD study for the years 2010 to 2019. In the GBD study, CUD is defined by ICD-10 or DSM-IV criteria for cannabis dependence and prevalence estimates are based on school and adult survey data. In brief, cannabis use prevalence estimates were first converted into regular use estimates and then into CUD estimates. The first conversion ratio was determined using a meta-analytical approach, resulting in a factor of 2¢9 . The second conversion ratio was determined using a Bayesian meta-regression, which accounted for risk differences between youth and adults. For more details on the estimation of CUD, see supplement of .All available data were retrieved from the indicated data sources, however, for prevalence of use, potency and TDI, data were missing for some countries and years. To obtain country- and year-specific CUD estimates for the 15 to 64 year old target population, age-specific data were aggregated using UN population data. Using TDI data, treatment rates, expressed as the number of treatment entries per 100,000 adults were estimated. We calculated the share of daily users among past-month users as an indicator for high-risk consumption patterns for countries with available data. This indicator sheds light on differences in use patterns between countries.
To obtain European averages across all countries with available data, population-weighted means of the indicators were calculated using UN population data. For THC concentrations, weighted averages would have required to account for the respective share of both resin and herbal cannabis in total use per country, however, these data were not available. Thus, we aggregated the country-level estimates by reporting medians and inter-quartile ranges.All data were analysed using R version 4¢0¢5 and are available as Supplementary Material 2, including the corresponding R code. Given the lack of uncertainty intervals for most indicators, meta analytical trend analyses were not feasible. For estimating changes in the indicators at the European level, the oldest and most recent data points were selected and reported. For prevalence of use, at least one of these two points was not available in four countries , which were excluded from estimating changes. The difference in adult and age specific prevalence of use as well as for THC levels did not account for the degree of uncertainty associated with each point estimate, as these data were not available from the EMCDDA data repository.To describe country-level trends in prevalence of use and CUD, statistical models were not applied as too few data points were available for most countries or because the estimates were predicted from statistical models . Thus, for these two indicators, we only compared the first and last available estimate in each country to estimate changes from the oldest to the most recent data point. To describe country-level trends in treatment rates and THC concentrations, linear regression models were conducted, separately for each country with at least 5 observations. In each model, year was entered as a single covariate, describing the annual change score in the outcome.
Results are reported for all models in which the coefficient was significantly different from 0 at alpha = 1%.The most recent estimates of prevalence of use are summarized in the map in Figure 1. Overall, cannabis use appears to be more common in Western than in Eastern countries. Based on data collected between 2013 and 2019, past-month prevalence of use was below 1% in Malta, Hungary, and Turkey. In three countries , between 5 and 6% of adults reported past month cannabis use. Highest use rates were recorded in Spain and France . The country-level cannabis use prevalence rates are further reported in Supplemental Material 1 . Re-examining the available EMCDDA data for all countries since 2010 allowed for a more precise analyses of trends of cannabis use in Europe. At the European level,trimming trays for weed cannabis consumption appeared to have increased in the past decade. Comparing the last and first available estimates, an increasing past-month prevalence was identified for 24 out of 26 countries that had at least two data points available. The country-specific changes in prevalence of use for the adult population are further illustrated in Supplemental Material 1 . Age-specific comparisons of first versus last years suggest that an increase in both past-month and past-year use was observed across all age groups in Europe . Among younger adults, cannabis consumption is overall more prevalent and absolute increases were more pronounced in this age group. Among 35 to 64 year-olds, increases were smaller in absolute terms but greater in relative terms. In this age group, prevalence of use increased by 50% or more between 2010 and 2019. The age-specific trends in prevalence of past-month use at the country level, based on the first and last available estimate, are further displayed in Figure 2. Only in Czechia and Poland, marked decreases in prevalence of use in most if not all age groups were observed.
In France, the Netherlands, and Spain, pronounced increases among middle-aged adults were identified. In contrast, Germany reports increases in total use which were driven mostly by younger adults. Very similar country patterns were present for age specific changes in past-year prevalence . Prevalence estimates for daily cannabis use among 15 to 64 year olds are displayed in Supplemental Figure 4. In 18 countries out of 26 countries with available data, indications for increasing trends in daily cannabis use could be observed.Most pronounced increases were reported in Portugal and Spain . Based on the last available estimates, the share of daily users among past-month users differed largely across all European countries. In countries like Lithuania, Czechia, Bulgaria and Poland, less than one in ten users reported high-risk use patterns. In contrast, 50% and 70% of all past-month users reported daily use in Luxembourg and Portugal, respectively. In half of all countries examined, the share of past-month users engaging in daily use was 20% or higher .In 2019, 115,477 treatment entries were registered by 25 countries and reported to the EMCDDA. At the country level, vast differences in treatment rates are reported. In Bulgaria and Slovenia, less than 2 treatment entries for cannabis problems per 100,000 adults were recorded in 2019. In contrast, more than 100 treatment entries per 100,000 adults were registered in Malta. For an illustration of country-specific trends of treatment rates, see Supplemental Material 1 . Based on the 22 countries with available data in the years 2010 and 2019 , the rate of treatment entries for cannabis as primary problem per 100,000 adults increased from 27¢0 to 35¢1 .