Does liberalizing cannabis laws increase cannabis use?

Can drug policies modify cannabis use starting choice? Insights from criminalisation in Italy

A key question in the ongoing drug policy debate is whether legalising cannabis leads to an increase in cannabis use. In Europe although no country has yet moved to legalisation, many have decriminalised personal possession. However, some jurisdictions are still discussing increased sanctions or have further strengthened penalties for the possession of illicit substances in order to deter widespread cannabis use. This is the case in Italy, where a law introduced in 2006 and repealed in 2014 de facto criminalised personal drug possession, and a potential increase in penalties is currently being debated as a policy option. Despite the intense public debate surrounding the legal status of cannabis, limited empirical research has been conducted in Europe to assess the population-level effects of drug policy reforms, mainly due to data availability constraints. In this study, we analyse the effect of criminalisation on the age of onset of cannabis use using an unique dataset that combines seven waves (2001-2017) of the nationally representative Italian Population Survey on Alcohol and other Drugs with relevant socio-economic data. The final dataset comprises 77,650 observations. Leveraging the rare opportunity to examine the effects of a policy that remained in force for a limited period, our empirical investigation employs a Complementary Log-Log model to analyse the starting rate, that is, the transition rate from non-use to use. To do so, we use self-reported data on the age of first cannabis use. Our results suggest that the implementation of stricter punishments has a significant effect in reducing the likelihood of early cannabis use initiation. The observed impact of criminalisation is limited in younger ages and diminished as adulthood approaches. This paper also discusses other considerations related to the social costs of criminalisation, which should also be taken into account in the ongoing policy debate.

Health, safety, and socioeconomic impacts of cannabis liberalization laws: An evidence and gap map

Background

Globally, cannabis laws and regulations are rapidly changing. Countries are increasingly permitting access to cannabis under various decriminalization, medicalization, and legalization laws. With strong economic, public health, and social justice incentives driving these domestic cannabis policy reforms, liberalization trends are bound to continue. However, despite a large and growing body of interdisciplinary research addressing the policy-relevant health, safety, and socioeconomic consequences of cannabis liberalization, there is a lack of robust primary and systematic research that comprehensively investigates the consequences of these reforms.

Objectives

This evidence and gap map (EGM) summarizes the empirical evidence on cannabis liberalization policies. Primary objectives were to develop a conceptual framework linking cannabis liberalization policies to relevant outcomes, descriptively summarize the empirical evidence, and identify areas of evidence concentration and gaps.

Search Methods

We comprehensively searched for eligible English-language empirical studies published across 23 academic databases and 11 gray literature sources through August 2020. Additions to the pool of potentially eligible studies from supplemental sources were made through November 2020.

Selection Criteria

The conceptual framework for this EGM draws upon a legal epidemiological perspective highlighting the causal effects of law and policy on population-level outcomes. Eligible interventions include policies that create or expand access to a legal or decriminalized supply of cannabis: comprehensive medical cannabis laws (MCLs), limited medical cannabidiol laws (CBDLs), recreational cannabis laws (RCLs), industrial hemp laws (IHLs), and decriminalization of cultivations laws (DCLs). Eligible outcomes include intermediate responses (i.e., attitudes/behaviors and markets/environments) and longer-term consequences (health, safety, and socioeconomic outcomes) of these laws.

Data Collection and Analysis

Both dual screening and dual data extraction were performed with third person deconfliction. Primary studies were appraised using the Maryland Scientific Methods Scale and systematic reviews were assessed using AMSTAR 2.

Main Results

The EGM includes 447 studies, comprising 438 primary studies and nine systematic reviews. Most research derives from the United States, with little research from other countries. By far, most cannabis liberalization research focuses on the effects of MCLs and RCLs. Studies targeting other laws-including CBDLs, IHLs, and DCLs-are relatively rare. Of the 113 distinct outcomes we documented, cannabis use was the single most frequently investigated. More than half these outcomes were addressed by three or fewer studies, highlighting substantial evidence gaps in the literature. The systematic evidence base is relatively small, comprising just seven completed reviews on cannabis use (3), opioid-related harms (3), and alcohol-related outcomes (1). Moreover, we have limited confidence in the reviews, as five were appraised as minimal quality and two as low quality.

Authors’ Conclusions

More primary and systematic research is needed to better understand the effects of cannabis liberalization laws on longer-term-and arguably more salient-health, safety, and socioeconomic outcomes. Since most research concerns MCLs and RCLs, there is a critical need for research on the societal impacts of industrial hemp production, medical CBD products, and decriminalized cannabis cultivation. Future research should also prioritize understanding the heterogeneous effects of these laws given differences in specific provisions and implementation across jurisdictions.

Does drug decriminalization increase unintentional drug overdose deaths?: Early evidence from Oregon Measure 110

This paper evaluates the causal effect of drug decriminalization on unintentional drug overdose deaths in a context with relatively poor access to drug treatment services. Using the synthetic control method, I find that when Oregon decriminalized small amounts of drugs in February 2021, it caused 182 additional unintentional drug overdose deaths to occur in Oregon in 2021. This represents a 23% increase over the number of unintentional drug overdose deaths predicted if Oregon had not decriminalized drugs.

The Impact of Recreational Cannabis Legalization on Cannabis Use and Associated Outcomes: A Systematic Review

Background

Recreational cannabis legalization has become more prevalent over the past decade, increasing the need to understand its impact on downstream health-related outcomes. Although prior reviews have broadly summarized research on cannabis liberalization policies (including decriminalization and medical legalization), directed efforts are needed to synthesize the more recent research that focuses on recreational cannabis legalization specifically. Thus, the current review summarizes existing studies using longitudinal designs to evaluate impacts of recreational cannabis legalization on cannabis use and related outcomes.

Method

A comprehensive bibliographic search strategy revealed 61 studies published from 2016 to 2022 that met criteria for inclusion. The studies were predominantly from the United States (66.2%) and primarily utilized self-report data (for cannabis use and attitudes) or administrative data (for health-related, driving, and crime outcomes).

Results

Five main categories of outcomes were identified through the review: cannabis and other substance use, attitudes toward cannabis, health-care utilization, driving-related outcomes, and crime-related outcomes. The extant literature revealed mixed findings, including some evidence of negative consequences of legalization (such as increased young adult use, cannabis-related healthcare visits, and impaired driving) and some evidence for minimal impacts (such as little change in adolescent cannabis use rates, substance use rates, and mixed evidence for changes in cannabis-related attitudes).

Conclusions

Overall, the existing literature reveals a number of negative consequences of legalization, although the findings are mixed and generally do not suggest large magnitude short-term impacts. The review highlights the need for more systematic investigation, particularly across a greater diversity of geographic regions.

Adolescent Cannabis Use During a Period of Rapid Policy Change: Evidence From the PATH Study

PURPOSE

To determine whether shifts in various state-level cannabis policies are associated with individual-level changes in adolescent cannabis use following implementation.

METHODS

We use the restricted-access youth cohort of the PATH Study, a recent, longitudinal, and nationally representative dataset, to assess whether changes in cannabis policy affect youth cannabis use. Data include respondents aged 12 to 17 years across up to six repeated observations (N = 26,673). Hybrid (between-person and within-person) panel models are used to examine adolescent past-month cannabis use.

RESULTS

Within-person effects showed that the odds of past-month cannabis use are lower (odds ratio [OR] = 0.632; p < .05) in years when a respondent's state allowed only cannabidiol (CBD) compared to years when the state had legalized medical cannabis. The odds of past-month cannabis use are lower during years when a respondent's state had decriminalized (OR = 0.617; p < .01) or criminalized (OR = 0.648; p < .05) adult recreational cannabis possession compared to years when it was legalized. These effects were robust to numerous controls, including time and state fixed effects. By contrast, significant between-person effects became nonsignificant with state fixed effects included, implying that state-level average use distinguishes average differences between states rather than policy.

DISCUSSION

Liberalized cannabis policy is significantly associated with recent adolescent cannabis use. The most consequential policy shift associated with adolescent use is from either criminalization or decriminalization of cannabis possession to legalization, such that states making these changes should consider additional prevention efforts.

Deterrence effect of penalties upon adolescent cannabis use

OBJECTIVE

Penalties are used in an effort to curtail drug use by citizens in most societies. There are growing calls for a reduction or elimination of such penalties. Deterrence theory suggests that use should increase if penalties reduce and vice versa. We sought to examine the relationship between changes to penalties for drug possession and adolescent cannabis use.

METHOD

Ten instances of penalty change occurred in Europe between 2000 and 2014, seven of which involved penalty reduction and three involved penalty increase. We conducted a secondary analysis of a series of cross-sectional surveys of 15-16-year-old school children, the ESPAD surveys, which are conducted every four years. We focused on past month cannabis use. We anticipated that an eight-year time span before and after each penalty change would yield two data points either side of the change. A simple trend line was fitted to the data points for each country.

RESULTS

In eight cases, the trend slope in past month cannabis use was in the direction predicted by deterrence theory, the two exceptions being the UK policy changes. Using the principals of binomial distributions, the likelihood of this happening by chance is 56/1024 = 0.05. The median change in the baseline prevalence rate was by 21%.

CONCLUSIONS

The science seems far from settled on this issue. There remains a distinct possibility that reducing penalties could contribute to small increases in adolescent cannabis use and consequently increase cannabis-related harms. This possibility should be considered in any political decision-making influencing drug policy changes.

The ethics and management of cannabis use in pregnancy following decriminalisation and licensing for medical use: narrative review

AIMS AND METHOD

As drug policies pertaining to cannabis use become more liberalised, the prevalence of cannabis use in pregnancy could increase. However, there is limited guidance available for clinicians. This paper presents a narrative review of literature published in the past 16 years (2006-2021) to (a) address the impact of legalisation and decriminalisation on the risks, ethics and support of women who use cannabis during pregnancy and (b) develop guidance for clinicians.

RESULTS

Both national and international trends suggest increased use of cannabis over the past decade, while the risks of cannabis use for recreational or medicinal purposes in pregnancy remain unmitigated.

CLINICAL IMPLICATIONS

This review confirmed that the recommendation of cannabinoid-based products for pregnant and breast-feeding women is currently premature. More research is needed to address safety concerns. We discussed navigating ethical concerns and suggest targeted management strategies for clinicians treating pregnant women who choose to use cannabis.

Attitudes and beliefs of medical students on cannabis in Hong Kong

BACKGROUND

To assess Hong Kong medical students' knowledge, attitudes and beliefs on cannabis and its future legal reform.

METHODS

A cross-sectional anonymous online survey were sent from 1st December 2018 to 31st August 2020 to all medical students from the Li Ka Shing Faculty of Medicine, the University of Hong Kong (HKU).

RESULTS

187 students (13.6 %) responded the survey. Overall, students perceived cannabis possessed significant physical and mental health risks, but they were more neutral to its physical and mental benefits. They also supported legalizing cannabis more so for medical use than recreational use. Females perceived higher risks than males. Those who used cannabis before were more acceptable to recommend cannabis as medical treatments, perceived cannabis use with greater benefits and less risks, and were more likely to support legal reform for cannabis in Hong Kong than their counterparts. Students were also more likely to recommend medical cannabis than non-licensed cannabis to patients if they were legally available.

CONCLUSION

Medical students in Hong Kong supported legalization of cannabis for medical use despite perceiving significant risks from cannabis use. Future research should investigate public acceptance on medical cannabis in Hong Kong and other Asian countries.

Changes in cannabis policy and prevalence of recreational cannabis use among adolescents and young adults in Europe-An interrupted time-series analysis

Background

Cannabis policy varies greatly across European countries, but evidence of how such policy impacts on recreational cannabis use among young people is conflicting. This study aimed to clarify this association by investigating how changes in cannabis legislation influenced cannabis use.

Methods

Available data on self-reports of recreational cannabis use among individuals aged 15–34 years was retrieved from EMCDDA. Information on cannabis policy changes was categorized as more lenient (decriminalisation or depenalisation) or stricter (criminalisation, penalisation). Countries that had implemented changes in cannabis legislation or had information on prevalence of use for at least eight calendar years, were eligible for inclusion. We used interrupted time-series linear models to investigate changes in country-specific trajectories of prevalence over calendar time and in relation to policy changes.

Results

Data from Belgium, Czech Republic, Germany, Italy, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden and United Kingdom, for 1994–2017 was available for analyses. Cannabis use varied considerably over the study period and between countries. On average, use was stable or weakly increasing in countries where legislation was not changed or changed at the extremes of the study period (+0.08 percent per year [95% CI -0.01, 0.17 percent]). In contrast, the pooled average use decreased after changes in legislation, regardless of whether it had become more lenient (-0.22 [-1.21, 0.77]) or stricter (-0.44 [-0.91, 0.03]).

Conclusions

Our findings do not support any considerable impact of cannabis legislation on the prevalence of recreational cannabis use among youth and young adults in Europe.

Trends in youth cannabis use across cannabis legalization: Data from the COMPASS prospective cohort study

Canada legalized recreational cannabis use for adults on October 17, 2018 with decision-makers emphasising the need to reduce cannabis use among youth. We sought to characterise trends of youth cannabis use before and after cannabis legalization by relying on a quasi-experimental design evaluating cannabis use among high school students in Alberta, British Columbia, Ontario, and Québec who participated in the COMPASS prospective cohort study. Overall trends in use were examined using a large repeat cross-sectional sample (n = 102,685) at two time points before legalization (16/17 and 17/18 school years) and one after (18/19 school year). Further differential changes in use among students affected by legalization were examined using three sequential four-year longitudinal cohorts (n = 5,400) of students as they progressed through high school. Youth cannabis use remains common with ever-use increasing from 30.5% in 2016/17 to 32.4% in 2018/19. In the repeat cross-sectional sample, the odds of ever use in the year following legalization were 1.05 times those of the preceding year (p = 0.0090). In the longitudinal sample, no significant differences in trends of cannabis use over time were found between cohorts for any of the three use frequency metrics. Therefore, it appears that cannabis legalization has not yet been followed by pronounced changes on youth cannabis use. High prevalence of youth cannabis use in this sample remains a concern. These data suggest that the Cannabis Act has not yet led to the reduction in youth cannabis use envisioned in its public health approach.

Cannabis Policy Changes and Adolescent Cannabis Use: Evidence from Europe

Cannabis accounts for the largest share of the illicit drug market, with a high prevalence of use even among adolescents. To tackle this longstanding problem, many kinds of reforms to national cannabis control policies have been implemented in Europe, but their effectiveness is still unclear. This paper analyses the association between selected categories of cannabis policy reforms and changes in perceived cannabis availability and patterns of use among adolescents. Data from 20 European countries across 15 years were drawn from a novel database of the European school Survey Project on Alcohol and other Drugs (ESPAD). Our analysis is based on a Difference-in-Differences design, which application is allowed by the fact that only thirteen out of the twenty countries included implemented policy changes. The results suggest that selected categories of reforms influence the availability and prevalence of cannabis use. In particular, some forms of restrictive intervention reduce the general prevalence of use and more liberal reforms seem linked to an increase in the share of students initiating use of cannabis. We find no evidence of an effect of policy changes on the share of frequent users, which are presumably those more likely to develop use-related health consequences.

Impact evaluations of drug decriminalisation and legal regulation on drug use, health and social harms: a systematic review

OBJECTIVES

To review the metrics and findings of studies evaluating effects of drug decriminalisation or legal regulation on drug availability, use or related health and social harms globally.

DESIGN

Systematic review with narrative synthesis.

DATA SOURCES

We searched MEDLINE, Embase, PsycINFO, Web of Science and six additional databases for publications from 1 January 1970 through 4 October 2018.

INCLUSION CRITERIA

Peer-reviewed articles or published abstracts in any language with quantitative data on drug availability, use or related health and social harms collected before and after implementation of de jure drug decriminalisation or legal regulation.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers screened titles, abstracts and articles for inclusion. Extraction and quality appraisal (modified Downs and Black checklist) were performed by one reviewer and checked by a second, with discrepancies resolved by a third. We coded study-level outcome measures into metric groupings and categorised the estimated direction of association between the legal change and outcomes of interest.

RESULTS

We screened 4860 titles and 221 full-texts and included 114 articles. Most (n=104, 91.2%) were from the USA, evaluated cannabis reform (n=109, 95.6%) and focussed on legal regulation (n=96, 84.2%). 224 study outcome measures were categorised into 32 metrics, most commonly prevalence (39.5% of studies), frequency (14.0%) or perceived harmfulness (10.5%) of use of the decriminalised or regulated drug; or use of tobacco, alcohol or other drugs (12.3%). Across all substance use metrics, legal reform was most often not associated with changes in use.

CONCLUSIONS

Studies evaluating drug decriminalisation and legal regulation are concentrated in the USA and on cannabis legalisation. Despite the range of outcomes potentially impacted by drug law reform, extant research is narrowly focussed, with a particular emphasis on the prevalence of use. Metrics in drug law reform evaluations require improved alignment with relevant health and social outcomes.

The impact of cannabis access laws on opioid prescribing

While recent research has shown that cannabis access laws can reduce the use of prescription opioids, the effect of these laws on opioid use is not well understood for all dimensions of use and for the general United States population. Analyzing a dataset of over 1.5 billion individual opioid prescriptions between 2011 and 2018, which were aggregated to the individual provider-year level, we find that recreational and medical cannabis access laws reduce the number of morphine milligram equivalents prescribed each year by 11.8 and 4.2 percent, respectively. These laws also reduce the total days' supply of opioids prescribed, the total number of patients receiving opioids, and the probability a provider prescribes any opioids net of any offsetting effects. Additionally, we find consistent evidence that cannabis access laws have different effects across types of providers, physician specialties, and payers.

Trends of poly-substance use among Canadian youth

INTRODUCTION

Poly-substance use, increasingly understood as a behaviour with uniquely adverse consequences, is on the rise among Canadian youth. High levels of e-cigarette vaping and the recent legalization of recreational cannabis use may result in an acceleration of this trend. The aim of this work was to characterise changes in youth poly-substance use over time, generate baseline data for future investigations, and highlight areas of interest for policy action.

METHODS

Descriptive statistics and regression models explored patterns and trends in concurrent use of multiple substances (alcohol, cigarettes, cannabis, and e-cigarettes) among Canadian high school students taking part in the COMPASS prospective cohort study during Y2 (2013/2014; n = 45,298), Y3 (2014/2015, n = 42,355), Y4 (2015/2016; n = 40,436), Y5 (2016/2017; n = 37,060), and Y6 (2017/2018; n = 34,879).

RESULTS

Poly-substance use increased significantly over time, with over 50% of students who used substance reporting past-year use of multiple substances by 2017/2018. Male and Indigenous students were significantly more likely to report poly-substance use than female and white students respectively. E-cigarette vaping doubled from Y5 to Y6 and was included in all increasingly prevalent substance use combinations.

CONCLUSIONS

Youth poly-substance use, rising since 2012/2013, saw a particularly steep increase after 2016/2017. Differential effects were observed for distinct demographic subpopulations, indicating tailored interventions may be required. E-cigarette vaping surged in parallel with the observed increase, suggesting a key role for this behaviour in shaping youth poly-substance use.

Social and public health implications of the legalisation of recreational cannabis: A literature review

BACKGROUND

After many years of legal struggles for the legalisation of recreational use of cannabis, the Constitutional Court of South Africa ruled in favour of the applicants in September 2018. Although the ruling issued caution regarding the social challenges accompanying this legalisation, it did not address how the country would deal with the societal consequences of this ruling.

AIM

The aim of this article was to discuss the social and public health implications of the legalisation of recreational cannabis on South Africa.

METHODS

Literature review on the social, health and legal impacts of legalisation of cannabis, considering experiences of other countries that have legalised cannabis.

RESULTS

The legalisation brings a range of significant negative consequences, which include an expected increase in the number of users and the subsequent undesirable effects on the physical, mental and social health of communities.

CONCLUSION

In terms of financial, infrastructural and human resources, South Africa cannot afford the consequences of the legalisation of recreational cannabis. Poor communities, children and the youth will carry the brunt of the scourge of cannabis use.

Does liberalisation of cannabis policy influence levels of use in adolescents and young adults? A systematic review and meta-analysis

OBJECTIVES

To examine the effect of cannabis policy liberalisation (decriminalisation and legalisation) levels of use in adolescents and young adults.

DESIGN

Systematic review and meta-analysis.

INCLUSION CRITERIA

Included studies were conducted among individuals younger than 25 years and quantitatively assessing consequences of cannabis policy change. We excluded articles: (A) exclusively based on participants older than 25 years; (B) only reporting changes in perceptions of cannabis use; (C) not including at least two measures of cannabis use; (D) not including quantitative data; and (E) reviews, letters, opinions and policy papers. PubMed, PsycINFO, Embase and Web of Science were searched through 1 March 2018.

DATA EXTRACTION AND SYNTHESIS

Two independent readers reviewed the eligibility of titles and abstracts and read eligible articles, and four authors assessed the risk of bias (Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies). Extracted data were meta-analysed. The protocol was registered with PROSPERO.

RESULTS

3438 records were identified via search terms and four via citation lists; 2312 were retained after removal of duplicates, 99 were assessed for eligibility and 41 were included in our systematic review. 13 articles examined cannabis decriminalisation, 20 examined legalisation for medical purposes and 8 examined legalisation for recreational purposes. Findings regarding the consequences of cannabis decriminalisation or legalisation for medical purposes were too heterogeneous to be meta-analysed. Our systematic review and meta-analysis suggest a small increase in cannabis use among adolescents and young adults following legalisation of cannabis for recreational purposes (standardised mean difference of 0.03, 95% CI -0.01 to -0.07). Nevertheless, studies characterised by a very low/low risk of bias showed no evidence of changes in cannabis use following policy modifications.

CONCLUSIONS

Cannabis policy liberalisation does not appear to result in significant changes in youths' use, with the possible exception of legalisation for recreational purposes that requires monitoring.

TRIAL REGISTRATION NUMBER

CRD42018083950.

Prelegalisation patterns and trends of cannabis use among Canadian youth: results from the COMPASS prospective cohort study

OBJECTIVE

Canada federally legalised recreational cannabis use among adults in October 2018. The impact this will have on Canadian youth is cause for concern. The current study examined changes in youth cannabis use over the time prior to legalisation to explore the impact of the beginning federal discourse around legalisation during the 2016/2017 school year.

DESIGN

COMPASS, a prospective cohort study based on annual self-administered questionnaires.

SETTING

Ontario and Alberta during the first 6 years of the COMPASS study (2012/2013 to 2017/2018).

PARTICIPANTS

Canadian grade 9-12 students attending secondary schools participating in COMPASS. In total, 2 30 404 questionnaires were included in the analysis (Y1: 2012/2013, n=24 173; Y2: 2013/2014, n=45 298; Y3: 2014/2015, n=42 355, Y4: 2015/2016, n=40 436; Y5: 2016/2017, n=37 060; Y6: 2017/2018, n=34 897).

PRIMARY AND SECONDARY OUTCOME MEASURES

Lifetime cannabis use, past-year cannabis use, weekly cannabis use, ease of access to cannabis and age at first cannabis use.

RESULTS

Cannabis never-use decreased between Y5 and Y6. Changes in age at first cannabis use mirrored this trend, with male students consistently starting younger. Cannabis access rates increased from Y4, mainly led by female students. Lifetime and past-year use rates were lowest in Y4 then increased in Y5 and Y6 due to a rise in the occasional use more common among female students, who reported use increases first. Non-white students were more likely use cannabis, with black and Aboriginal students the only two groups consistently reporting more weekly than occasional use, though with opposing trajectories. Overall, Aboriginal students had the highest odds of reporting lifetime, past-year and weekly use among the demographic groups examined.

CONCLUSION

After a steady decrease in patterns of cannabis among youth over several years, it appears that there has been a gradual increase in cannabis use among youth following the start of discourse around cannabis legalisation, with some populations of youth being at greater risk.

Trends in cannabis use over time among Canadian youth: 2004-2014

Cannabis is the most commonly used illicit substance among Canadian youth. The current study examined national trends in cannabis use among Canadian youth from 2004/05 to 2014/15 using nationally representative data from the Canadian Student Tobacco, Alcohol and Drugs Survey (CSTADS). Data were collected from students in Grades 7 to 12 as part of the Canadian Student Tobacco, Alcohol and Drugs Survey (formerly the Youth Smoking Survey) using a repeat-cross sectional survey across 6 biennial survey waves between 2004 and 2014 (N = 243,057). Regression models examined factors associated with cannabis use in the past 12 months, perceived ease of access, and a multilinear regression examined age of initiation across survey cycles. The findings indicate that use of cannabis in the past 12-months significantly decreased among Canadian youth. Past-year use peaked in 2008/09 at 27.3%; compared to 16.5%, in 2014/15. Mean age of initiation did not vary over time, while youth in recent cycles reported that cannabis was more difficult to access: in 2006/07, 77.1% reported that it would be easy to access cannabis compared to 49.0% in 2014/15. Overall, cannabis use among Canadian youth appears to have peaked around 2008/09, with substantial declines over the past decade. It will be critically important to examine any changes in patterns of use following legalization of non-medical cannabis in Canada.

Cannabis decriminalization: A study of recent policy change in five U.S. states

BACKGROUND

A number of public health professional organizations support the decriminalization of cannabis due to adverse effects of cannabis-related arrests and legal consequences, particularly on youth. We sought to examine the associations between cannabis decriminalization and both arrests and youth cannabis use in five states that passed decriminalization measures between the years 2008 and 2014: Massachusetts (decriminalized in 2008), Connecticut (2011), Rhode Island (2013), Vermont (2013), and Maryland (2014).

METHODS

Data on cannabis possession arrests were obtained from federal crime statistics; data on cannabis use were obtained from state Youth Risk Behavior Survey (YRBS) surveys, years 2007-2015. Using a "difference in difference" regression framework, we contrasted trends in decriminalization states with those from states that did not adopt major policy changes during the observation period.

RESULTS

Decriminalization was associated with a 75% reduction in the rate of drug-related arrests for youth (95% CI: 44%, 89%) with similar effects observed for adult arrests. Decriminalization was not associated with any increase in the past-30 day prevalence of cannabis use overall (relative change=-0.2%; 95% CI: -4.5%, 4.3%) or in any of the individual decriminalization states.

CONCLUSIONS

Decriminalization of cannabis in Massachusetts, Connecticut, Rhode Island, Vermont, and Maryland resulted in large decreases in cannabis possession arrests for both youth and adults, suggesting that the policy change had its intended consequence. Our analysis did not find any increase in the prevalence of youth cannabis use during the observation period.

Medical Marijuana Legalization and Marijuana Use Among Youth in Oregon

While the legalization of marijuana for medical and recreational use has raised concerns about potential influences on marijuana use and beliefs among youth, few empirical studies have addressed this issue. We examined the association between medical marijuana patients and licensed growers per 1000 population in 32 Oregon counties from 2006 to 2015, and marijuana use among youth over the same period. We obtained data on registered medical marijuana patients and licensed growers from the Oregon Medical Marijuana Program and we obtained data on youth marijuana use, perceived parental disapproval, and demographic characteristics from the Oregon Healthy Teens Survey. Across 32 Oregon counties, the mean rate of marijuana patients per 1000 population increased from 2.9 in 2006 to 18.3 in 2015, whereas the grower rate increased from 3.8 to 11.9. Results of multi-level analyses indicated significant positive associations between rates of marijuana patients and growers per 1000 population and the prevalence of past 30-day marijuana use, controlling for youth demographic characteristics. The marijuana patient and grower rates were also inversely associated with parental disapproval of marijuana use, which decreased from 2006 to 2015 and acted as a mediator. These findings suggest that a greater number of registered marijuana patients and growers per 1000 population in Oregon counties was associated with a higher prevalence of marijuana use among youth from 2006 to 2015, and that this relationship was partially attributable to perceived norms favorable towards marijuana use.

Cigarette use is increasing among people with illicit substance use disorders in the United States, 2002-14: emerging disparities in vulnerable populations

BACKGROUND AND AIMS

While cigarette smoking has declined over time, it is not known whether this decline has occurred similarly among individuals with substance use disorders (SUDs) in the United States (US). The current study estimated trends in smoking from 2002 to 2014 among US individuals with and without SUDs.

DESIGN

Linear time trends of current smoking prevalence were assessed using logistic regression models.

SETTING

United States; data were drawn from the 2002 to 2014 National Household Survey on Drug Use (NSDUH), an annual US cross-sectional study.

PARTICIPANTS

A representative, population-based sample of US individuals age 12 yeas and older (total analytical population: n = 723 283).

MEASUREMENTS

Past-month current smoking was defined as having smoked at least 100 lifetime cigarettes and reporting smoking part or all of at least one cigarette during the past 30 days. Respondents were classified as having any SUD if they met criteria for abuse or dependence for one or more of the following illicit drugs: cannabis, hallucinogens, inhalants, tranquilizers, cocaine, heroin, pain relievers, simulants and sedatives. A second SUD variable included all drugs listed above excluding cannabis use disorder (CUD). An additional variable included respondents who met criteria for cannabis abuse or dependence.

FINDINGS

Among those with any SUD, the prevalence of smoking did not change from 2002 to 2014 (P = 0.08). However, when CUDs were separated from other SUDs, a significant increase in prevalence of smoking was observed among those with SUDs excluding CUDs (P < 0.001), while smoking decreased among those with CUDs (P < 0.001). Smoking declined among those without SUDs (P < 0.001). In 2014, smoking remained significantly more common among those with any SUD (55.48%), SUDs excluding CUDs (63.34%) and CUDs (51.34%) compared with those without these respective disorders (18.16, 18.55 and 18.64%; P < 0.001).

CONCLUSIONS

The prevalence of cigarette smoking in the United States increased from 2002 to 2014 among people with substance use disorders (SUDs) excluding cannabis use disorders (CUDs) and declined among those with CUDs and without SUDs. In 2014, the prevalence of smoking was multifold higher among those with SUDs, including CUDs, compared with those without SUDs.

Ready, willing, and able: the role of cannabis use opportunities in understanding adolescent cannabis use

AIMS

To examine adolescent cannabis use-both at national and individual levels-by deconstructing it into its necessary conditions of realistic use opportunities and willingness to use the drug given such opportunities.

DESIGN

Nationally representative, repeated cross-sectional survey.

SETTING

Norway.

PARTICIPANTS

A total of 8818 16-year-olds who participated in the European School Survey Project on Alcohol and Other Drugs (ESPAD) in 2007, 2011, and 2015.

MEASUREMENTS

Adolescent reports concerning their life-time 'cannabis use' and 'possibilities to use cannabis' were used to assess: (a) overall cannabis use, (b) exposure to realistic cannabis use opportunities, and (c) cannabis use among those exposed to use opportunities. Logistic regression models were used to estimate national trends since 2007 in these indicators, and to identify individual-level factors associated with cannabis use versus non-use among youth exposed to concrete use opportunities.

FINDINGS

Prevalence of life-time cannabis use remained stably low, averaging 6.4% across the three surveys. Life-time exposure to cannabis use opportunities decreased [odds ratio (OR)_{ESPAD assessment}  = 0.90, 95% confidence interval (CI) = 0.84-0.97, P = 0.006], yet cannabis use among adolescents with such opportunities increased significantly (OR_{ESPAD assessment}  = 1.17, 95% CI = 1.03-1.34, P = 0.02) since 2007. After controlling for a range of other risk factors, abstinence from alcohol intoxication and cigarette use, as well as the perceptions of even minimal cannabis use as risky remained the factors most robustly associated with lower likelihood of cannabis use among youth with realistic use opportunities.

CONCLUSIONS

Approaches accounting for realistic use opportunities proved critical in our understanding of underage cannabis use, both at the national and individual level, and may be informative for development of prevention strategies in the era of cannabis liberalization. In addition, delineation of realistic opportunities from behaviours conditioned upon such opportunities is generalizable to a range of public health issues.

Cannabis decriminalization and the age of onset of cannabis use

BACKGROUND

In the Czech Republic in 2010 a law was introduced decriminalizing personal possession of small quantities of several illicit drugs, including cannabis.

METHODS

We use 2012 survey data to examine the effect of a change in cannabis policy on the age of onset of cannabis use. We estimate the effect of the policy change using a mixed proportional hazards framework that models the transition to first cannabis use.

RESULTS

The change in cannabis policy did not affect the transition to first cannabis use.

CONCLUSION

We find no evidence of cannabis decriminalization affecting the age of onset of cannabis use.

Prevalence and correlates of cannabis use among athletes-A systematic review

BACKGROUND AND OBJECTIVES

Despite scientific evidence that marijuana impairs performance and mental health, there is evidence that some athletes are at higher risk for use. This review aims to identify possible risk factors associated with marijuana use in athletes.

METHODS

A search was conducted in the PubMed database with the keywords: (marijuana OR cannabis OR tetrahydrocannabinol OR delta-9-tetrahydrocannabinol OR THC) AND (sports OR sport OR athlete OR athletes). We retrieved 186 studies. After applying the inclusion/exclusion criteria, 15 studies remained for review.

RESULTS

The review revealed a number of potential risk factors for marijuana use among adult athletes, including being male, Caucasian, using sport performance-enhancing drugs, using marijuana to enhance recreation or non-sport performance, and practicing specific types of sports including skeleton, bobsleding, and ice hockey. Contrary to use patterns in the general population, among athletes marijuana appears to take the place of tobacco as the second most widely used drug, after alcohol. Many elite athletes denied the use of marijuana, which suggests that toxicological testing is an important tool for identifying users, because it is more accurate than self-report. Geography appears important, as in areas of high consumption, prevalence among athletes appears to be greater as well.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Contrary to the image that athletes do not use psychoactive drugs, this review suggests that a number of athletic subgroups are at increased risk for marijuana use. Surprisingly, a common rationale for use appears to be to enhance sports performance. As in the general population, experimentation starts early-in pre-adolescence-at an age that prevention and guidance programs could have positive influences. (Am J Addict 2016;25:518-528).

Influence of legal status on the uptake of cannabis in young people

PURPOSE OF REVIEW

Policies that limit young people's access to cannabis may reduce early onset of use and minimize health-related harm. This review article provides an update of recent research examining the influence of the cannabis policy frameworks on the use of cannabis by young people.

RECENT FINDINGS

There are significant concerns that ongoing policy changes in favour of legalization will increase the uptake of cannabis by young people. Evidence to support a causal effect of cannabis policy changes on increased uptake by young people is lacking; more time may be needed to assess the impact because the policies are still evolving. Policy changes in favour of legalization were associated with reduced risk perception although this may be a cause or consequence. The need to situate the impact of these policies in the context of specific policy features, social norms and perceptions about cannabis has been highlighted.

SUMMARY

A more nuanced understanding of the impact of the legal status of cannabis on young people is needed to build evidence for future policy options. The impact of these policies may not be immediately apparent but limiting young people's access to cannabis must be prioritized during policy deliberations.

Who are the adolescents saying "No" to cannabis offers

BACKGROUND AND AIMS

Adolescents who refuse direct cannabis offers and remain non-users represent a potentially very informative, yet surprisingly understudied group. We examined a range of risk and protective factors putatively associated with this poorly understood "cannabis-resilient" profile.

METHODS

Paper-and-pencil questionnaires assessing substance use, peer and family relations, and behavioral and personality characteristics were completed by 19,303 middle- and high-school students from 82 schools in Norway (response rate 84%)

RESULTS

The lifetime prevalence of cannabis use was 7.6%. Another 10.4% reported no use of the drug despite having received recent cannabis offers. Results from the multinomial logistic regression revealed a set of characteristics differentiating adolescents who resisted such offers from those who: (a) neither received the offers nor used, and, more importantly, (b) used the drug. Specifically, parent-child relationship quality, negative drug-related beliefs, absence of close relationships with cannabis-users, low delinquency, no regular tobacco use, and infrequent alcohol intoxication were all associated with increased odds of being in the cannabis-resilient vs. cannabis-user group. This pattern of results was comparable across middle- and high-school cohorts, but the parent-child relationship quality and delinquency were significantly associated with cannabis-resilient vs. cannabis-use outcome only among younger and older adolescents, respectively.

CONCLUSIONS

Among other low-risk characteristics, better relationships with parents and beliefs that drug use is problematic were associated with adolescents' refusals to accept cannabis offers. These results may have implications for novel preventive strategies targeting cannabis-exposed adolescents.

Comparative policy analysis for alcohol and drugs: Current state of the field

BACKGROUND

A central policy research question concerns the extent to which specific policies produce certain effects - and cross-national (or between state/province) comparisons appear to be an ideal way to answer such a question. This paper explores the current state of comparative policy analysis (CPA) with respect to alcohol and drugs policies.

METHODS

We created a database of journal articles published between 2010 and 2014 as the body of CPA work for analysis. We used this database of 57 articles to clarify, extract and analyse the ways in which CPA has been defined. Quantitative and qualitative analysis of the CPA methods employed, the policy areas that have been studied, and differences between alcohol CPA and drug CPA are explored.

RESULTS

There is a lack of clear definition as to what counts as a CPA. The two criteria for a CPA (explicit study of a policy, and comparison across two or more geographic locations), exclude descriptive epidemiology and single state comparisons. With the strict definition, most CPAs were with reference to alcohol (42%), although the most common policy to be analysed was medical cannabis (23%). The vast majority of papers undertook quantitative data analysis, with a variety of advanced statistical methods. We identified five approaches to the policy specification: classification or categorical coding of policy as present or absent; the use of an index; implied policy differences; described policy difference and data-driven policy coding. Each of these has limitations, but perhaps the most common limitation was the inability for the method to account for the differences between policy-as-stated versus policy-as-implemented.

CONCLUSION

There is significant diversity in CPA methods for analysis of alcohol and drugs policy, and some substantial challenges with the currently employed methods. The absence of clear boundaries to a definition of what counts as a 'comparative policy analysis' may account for the methodological plurality but also appears to stand in the way of advancing the techniques.

Cannabis Liberalization and Adolescent Cannabis Use: A Cross-National Study in 38 Countries

AIMS

To assess the associations between types of cannabis control policies at country level and prevalence of adolescent cannabis use.

SETTING, PARTICIPANTS AND DESIGN

Multilevel logistic regressions were performed on 172,894 adolescents 15 year of age who participated in the 2001/2002, 2005/2006, or 2009/2010 cross-sectional Health Behaviour in School-Aged Children (HBSC) survey in 38 European and North American countries.

MEASURES

Self-reported cannabis use status was classified into ever use in life time, use in past year, and regular use. Country-level cannabis control policies were categorized into a dichotomous measure (whether or not liberalized) as well as 4 detailed types (full prohibition, depenalization, decriminalization, and partial prohibition). Control variables included individual-level sociodemographic characteristics and country-level economic characteristics.

FINDINGS

Considerable intra-class correlations (.15-.19) were found at country level. With respect to the dichotomized cannabis control policy, adolescents were more likely to ever use cannabis (odds ratio (OR) = 1.10, p = .001), use in past year (OR = 1.09, p = .007), and use regularly (OR = 1.26, p = .004). Although boys were substantially more likely to use cannabis, the correlation between cannabis liberalization and cannabis use was smaller in boys than in girls. With respect to detailed types of policies, depenalization was associated with higher odds of past-year use (OR = 1.14, p = .013) and regular use (OR = 1.23, p = .038), and partial prohibition was associated with higher odds of regular use (OR = 2.39, p = .016). The correlation between cannabis liberalization and regular use was only significant after the policy had been introduced for more than 5 years.

CONCLUSIONS

Cannabis liberalization with depenalization and partial prohibition policies was associated with higher levels of regular cannabis use among adolescents. The correlations were heterogeneous between genders and between short- and long-terms.

Assessing the public health impacts of legalizing recreational cannabis use in the USA

A major challenge in assessing the public health impact of legalizing cannabis use in Colorado and Washington State is the absence of any experience with legal cannabis markets. The Netherlands created a de facto legalized cannabis market for recreational use, but policy analysts disagree about how it has affected rates of cannabis use. Some US states have created de facto legal supply of cannabis for medical use. So far this policy does not appear to have increased cannabis use or cannabis-related harm. Given experience with more liberal alcohol policies, the legalization of recreational cannabis use is likely to increase use among current users. It is also likely that legalization will increase the number of new users among young adults but it remains uncertain how many may be recruited, within what time frame, among which groups within the population, and how many of these new users will become regular users.

The four stages of youth sports TBI Policymaking: engagement, enactment, research, and reform

This article advances, for the first time, a framework for situating public health law interventions as occurring in a predictable four-stage process. Whether the intervention is related to mandatory seat-belt laws, HIV prevention through needle-exchanges, or distracted-driving laws, these public health law interventions have generally been characterized by the following four stages. First, a series of publicized incidents, observances, or outcomes generate significant media attention, and are framed as public health harms. Then, a few select states evaluate such harms and proactively seek testimony or evidence designed to support a law-based intervention. After this initial public engagement, states enact legal frameworks designed to minimize or reduce the harm, often in the absence of full information about the scope of harm or potential effectiveness of the intervention. In contrast, scholars have proposed that at these early stages, lawmaking should be evidence-based and “developed through a continuous process that uses the best available quantitative and qualitative evidence.”5 Our experience evaluating youth sports traumatic brain injury (TBI) lawmaking suggests that, like other public health issues with sudden and intense media (and, therefore, constituent) attention, an evidence-based approach was lacking during these early stages.