Trends in use of marijuana and attitudes toward marijuana among youth before and after decriminalization: the case of California 2007-2013

Changes in the incidence of cannabis-related disorders after the Cannabis Act and the COVID-19 pandemic in Québec, Canada

BACKGROUND

The Canadian Cannabis Act (CCA, implemented in October 2018) and the COVID-19 pandemic (April 2020) might have contributed to cannabis-related harms in Québec, known for its stringent cannabis legal framework. We explored changes in incidence rates of cannabis-related disorders (CRD) diagnoses associated with these events in Québec.

METHODS

We utilized linked administrative health data to identify individuals aged 15 year+ newly diagnosed with CRD during hospitalizations, emergency, and outpatients clinics across Québec, from January 2010 and March 2022 (147 months). Interrupted time-series analyses (ITSA) assessed differences (as percentage changes) in sex- and age-standardized, and sex-stratified, monthly incidence rates (per 100,000 population) attributed to the CCA and the COVID-19 pandemic, compared to counterfactual scenarios where pre-events trends would continue unchanged.

RESULTS

The overall monthly mean rates of incident diagnoses nearly doubled from the pre-CCA period (1.56 per 100,000 population) to the COVID-19 pandemic period (3.02 per 100,000 population). ITSA revealed no statistically significant level or slope changes between adjacent study periods, except for a decrease in the slope of incidence rates among males by 1.84 % (95 % CI -3.41 to -0.24) during the COVID-19 pandemic compared to the post-CCA period. During the post-CCA period, the trends of incidence rates in the general and male populations grew significantly by 1.22 % (95 % CI 0.08 to 2.35) and 1.44 % (0.04 to 2.84) per month, respectively. Similarly significant increases were observed for the general and female populations during the COVID-19 pandemic, with monthly rates rising by 1.43 % (95 % CI 0.75 to 2.12) and 1.75 % (95 % CI 0.13 to 3.37), respectively. These increases more than doubled pre-CCA rates.

CONCLUSIONS

The incidence rates of CRD diagnoses across Québec appears to have increased following the implementation of the CCA and during the COVID-19 pandemic. Our findings echo public health concerns regarding potential cannabis-related harms and are consistent with previous Canadian studies.

Marijuana Message Channels, Health Knowledge, Law Knowledge, and Confidence in Knowledge as Risk and Protective Factors of Marijuana Use among College Students

Marijuana use among U.S. college students is the highest since the mid-1980s. Because knowledge about marijuana and confidence in the knowledge are related to changing marijuana laws and marijuana-related messages ubiquitous in college students' information environment, we examined their relationships with use. The Structural Equation Modeling method was used to analyze the relationships using survey responses from 249 college students in an adult-use marijuana legal state. Marijuana health knowledge was related to less use, and law knowledge was related to more use. Both relationships were mediated by perceived risk. Confidence in knowledge was related to more use directly as well as indirectly via lower peer disapproval and lower perceived risk. Among various marijuana message channels, peers were the most influential, contributing to lower health knowledge and higher confidence in knowledge.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

Associations between adverse childhood experiences and substance use: A meta-analysis

BACKGROUND

Adverse childhood experiences (ACEs) can be associated with negative health outcomes such as substance use. However, extant literature assessing this association is mixed.

OBJECTIVE

The present meta-analysis was conducted to obtain a pooled effect size for the association between ACEs and substance use (i.e., smoking, problematic alcohol use, heavy alcohol use, illicit drug use, and cannabis use).

PARTICIPANTS AND SETTING

The present meta-analyses included 102 studies (N = 901,864), where 42.32 % of participants were male, and the mean age was 30.91 years.

METHODS

Searches were conducted in MEDLINE, Embase, and PsycINFO in August 2021 and moderators were examined. Inclusion criteria included studies that measured ACEs prior to age 18 and substance use, and were published in English. All analyses were completed in Comprehensive Meta-Analysis Software, Version 3.0 (Borenstein et al., 2009).

RESULTS

Pooled effect sizes between ACEs and smoking [OR = 1.803 (95 % CI 1.588, 2.048)], problematic alcohol use [OR = 1.812 (95 % CI 1.606, 2.044)], heavy alcohol use [OR = 1.537 (95 % CI 1.344, 1.758)], cannabis use [OR = 1.453 (95 % CI 1.184, 1.786)] and illicit drug use [OR = 1.695 (95 % CI 1.530, 1.878)] were significant. Significant moderators contribute to the understanding of the association between ACEs and substance use, and are discussed extensively.

CONCLUSIONS

ACEs confer risk for substance use and trauma-informed approaches to substance use treatment should be considered. Study limitations and implications are discussed.

Long-Term Impact of Medical Marijuana Laws on the Burden of Cannabis Use Disorders in US Male and Female Adolescents and Young Adults

Deregulation of cannabis use has raised concerns regarding its potential effects on health, particularly in adolescents and young adults. Here, we extracted data from the Global Burden of Disease database to estimate the long-term effect (> 5 years) of medical marijuana laws (MML) on 2019 cannabis use disorders Disability Adjusted Life Years (2019 CUD DALYs) in US male and female adolescents (15-19 years old) and young adults (20-24 years old). Socio-cultural, demographic and economic characteristics were used as baseline covariates. To improve the robustness of estimation, we took advantage of machine learning techniques. We found no significant effect of MML on 2019 CUD DALYS in each of our four age/sex groups. Estimates from a marginal structural model taking into account age and sex strata in the same model were also non-significant. Our findings suggest that MML may have a negligible effect (if any) on cannabis use disorders in this population group.

Impact of Cannabis Legalization on Adolescent Cannabis Use

Because of substantial limitations in available national data, such as inconsistencies among surveys and small sample sizes, the increased prevalence of cannabis use among adolescents since recreational legalization has not been directly observed. Nevertheless, both usage frequency and product potency have significantly increased, alongside alternative routes of delivery to smoking, such as vaping cannabis. Moreover, certain populations may be especially vulnerable to the effects of legalization. Regardless of differing state-level cannabis legalization status, the adverse consequences of cannabis on youth have clear negative impacts on mental health, medical symptoms, educational outcomes, and increased risk of addiction to other substances.

Sex Differences in the Relationship Between Early Adverse Childhood Experiences, Delinquency, and Substance Use Initiation in High-Risk Adolescents

Adverse childhood experiences (ACEs) have been linked to a host of subsequent negative health and behavioral problems. However, the role of sex in the ramifications of early ACEs remains unclear, particularly for delinquency and substance use initiation in adolescence. A small body of research has produced mixed findings on sex differences in the relationship between ACEs and antisocial outcomes in adolescence, resulting in uncertainty about whether and how ACEs may operate differently for boys and girls. The current study drew on a high-risk group of adolescents (N=2455; M_age=15.4; 48% female; 50% Black, 23% Hispanic) from the Fragile Families and Child Wellbeing Study to examine the associations between accumulated ACEs across early childhood, and delinquency and substance use initiation of alcohol, cigarette, and cannabis in adolescence. We utilized mother and father reports on the exposure to seven different types of ACEs (i.e., physical abuse, psychological abuse, neglect, parental substance misuse, parental mental illness, parental intimate partner violence, and parental criminal behavior) when adolescents were ages 1, 3, and 5. Total ACEs scores and their relationships with delinquency, and lifetime use of alcohol, cigarettes, and cannabis were assessed separately for girls and boys. Results suggested that accumulated ACEs during early childhood may be implicated in boys' delinquency, while ACEs were not significantly associated with girls' self-reported delinquency or for boys' and girls' substance use initiation. Findings suggest that the enduring consequences of ACEs may be sex-specific, and have implications for the development of policies to mitigate ACEs and their harms.

The influence of parent and peer disapproval on youth marijuana use mediated by youth risk perception: Focusing on the state comparison

BACKGROUND

The prevention of youth marijuana use has become a national priority in the United States. This study examined the influence of parent and peer disapproval on youth marijuana use, mediated by youth risk perception. Because the legal status of marijuana use can influence individual perceptions of the drug, this study investigated differences in the mediating mechanism between youth living in states with medical marijuana legalization (MML) and those living in non-MML states.

METHODS

The 2019 National Survey of Drug Use and Health was used with a youth population aged 12-17 years (N = 2293). Structural equation modeling and bias-corrected bootstrapping were used to examine hypothesized path models and to evaluate the mediating effect of youth risk perception.

RESULT

Findings demonstrated that parent and peer disapproval significantly increased youth risk perception of marijuana and reduced youth marijuana use. Second, youth risk perception significantly mediated the association between parent and peer disapproval and youth marijuana use. Third, parent disapproval had a more significant direct effect on youth marijuana use, while peer disapproval had a more significant indirect effect on youth marijuana use via youth risk perception. Finally, the results showed a similar pattern in the mechanism between youths living in MML states compared with those in non-MML states in terms of significance and direction.

CONCLUSION

The findings suggested a need for improvements in marijuana related policies for both MML and non-MML states. Moreover, parent and peer focused strategies for education and prevention concerning marijuana use among youth are emphasized.

Classifying risky cannabis involvement in young adults using the Marijuana Consequences Questionnaire (MACQ)

BACKGROUND

Despite the growing prevalence of cannabis use and associated consequences among U.S. young adults, relatively little is known about precisely what level of marijuana involvement may be problematic.

METHOD

With this study we sought to identify empirically-derived cut-scores for the Marijuana Consequences Questionnaire (MACQ) that would distinguish among levels of cannabis risk in a sample of young adult college students (N = 496). We also examined how these levels of cannabis risk corresponded to a variety of indicators of cannabis involvement, including frequency of use, intoxication, other measures of cannabis consequences, and indicators of more severe cannabis involvement (e.g., physiological dependence, loss of control over use, cannabis use disorder).

RESULTS

Receiver operating characteristic analyses yielded cutoffs that distinguished among three distinct levels of risk, "Low", "Moderate", and "High". These empirically derived cut scores showed strong overall differentiation among classifications, with good sensitivity and specificity. MACQ-based risk levels were validated across several indices of cannabis involvement. Cutoffs differed across genders.

CONCLUSIONS

Findings offer a new application for the MACQ, allowing for the identification of those at greatest risk. As such, this measure may be used to facilitate appropriately targeted intervention.

Impact of recreational cannabis legalization on cannabis use, other substance use, and drug-related offending among justice-system-involved youth

The present study assessed whether cannabis use, other types of substance use, and drug-related offending changed among 1216 justice-system-involved youth after recreational cannabis legalization. Using generalized estimating equation population-averaged models, we compared youth in California, where recreational cannabis is legalized, and Pennsylvania, where recreational use is still prohibited. Results indicated that cannabis use, cannabis selling, and driving under the influences (DUIs) increased more among Pennsylvanian than Californian youth. We found no changes in alcohol or noncannabis drug use after legalization. Cigarette use did not change significantly among Pennsylvanian youth, but Californian youth exhibited decreased cigarette use after legalization. Although not directly tested in the present analysis, it is possible that changes in state-level recreational cannabis policies throughout the U.S. may contribute to more permissive attitudes toward cannabis, which leads to higher use and use-related outcomes. Future research should continue to consider the potential impacts of legalization on other types of risky and illegal behavior.

Societal Costs and Outcomes of Medical and Recreational Marijuana Policies in the United States: A Systematic Review

Significant support exists in the United States for legalization of marijuana/cannabis. As of 2021, 36 states and four territories approved the legalization of medical cannabis via medical marijuana laws (MMLs), and 15 states and District of Columbia (DC) have adopted recreational marijuana laws (RMLs). We performed structured and systematic searches of articles published from 2010 through September 2021. We assess the literature pertaining to adolescent marijuana use; opioid use and opioid-related outcomes; alcohol use; tobacco use; illicit and other drug use; marijuana growing and cultivation; employment, earnings, and other workplace outcomes; academic achievement and performance; criminal activity; perceived harmfulness; traffic and road safety; and suicide and sexual activity. Overall, 113 articles satisfied our inclusion criteria. Except for opioids, studies on use of other substances (illicit drugs, tobacco, and alcohol) were inconclusive. MMLs and RMLs do not generate negative outcomes in the labor market, lead to greater criminal activity, or reduce traffic and road safety.

Association of Racial Disparity of Cannabis Possession Arrests Among Adults and Youths With Statewide Cannabis Decriminalization and Legalization

Question

How are statewide cannabis policies (eg, legalization, decriminalization, no policy change) associated with cannabis arrest rate racial disparities among adults and youths?

Findings

In this case-control study of 43 US states with and without cannabis policy changes, decriminalization and legalization were associated with large reductions in race-based arrests among adults; however, the timing of effects suggests differential policy effects. Among youth, only decriminalization was associated with reductions in arrests and arrest disparities; cannabis arrests for adults and youth increased over time in states that did not implement a cannabis policy change.

Meaning

The study findings suggest that increases in arrest rate disparities in states without legalization or decriminalization highlight the need for targeted interventions to address racial injustice.

Importance

Despite calls for cannabis decriminalization and legalization, research investigating the association of policy with arrest rates and racial disparities is scarce.

Objectives

To examine racial differences in cannabis arrest rates among adults and youths after statewide decriminalization, legalization, and no policy changes.

Design, Setting, and Participants

This case-control study used race-based arrest data from the Uniform Crime Reporting Program and Surveillance, Epidemiology, and End Results county-level population data from January 2000 through December 2019. Data were analyzed in July 2021. Event-study analyses based on the arrest rates from 43 US states were conducted to compare preimplementation and postimplementation differences in arrest rates for states with decriminalization, legalization, and no policy changes.

Exposures

Nine states implemented legalization, 8 implemented decriminalization, and 26 had no policy change.

Main Outcomes and Measures

Outcome measures were cannabis arrest rates for Black and White adults and youths per year and by state, while controlling for several covariates.

Results

Rates were reported per 100 000. When comparing absolute differences in arrests from January to December 2008 (before policy changes) to January to December 2019, legalization was associated with 561 and 195 fewer arrests and decriminalization with 448.6 and 117.1 fewer arrests for Black and White adults, respectively. States without a policy change saw reductions of 47.5 and 33.0 arrests for Black and White adults, respectively. Among youth, legalization was associated with 131.1 and 131.2 fewer arrests and decriminalization with 156.1 and 124.7 fewer arrests for Black and White youths, respectively. Among states without a policy change, arrests reduced by 35 and 52.4 for Black and White youths, respectively. Plotted trends of the arrest ratios from January 2000 through December 2019 suggests racial disparities remained over time. Event-study analyses suggest that decriminalization was associated with an arrest rate reduction for Black and White adults and youths. The timing of reductions suggests differential policy effects. Arrest disparities increased in states that did not have a cannabis policy change.

Conclusions and Relevance

In this case-control study of states with and without cannabis decriminalization and legalization policies, increased arrest rate disparities in states without either policy highlight the need for targeted interventions to address racial injustice.

The Intersection Between Sex and Race in Understanding Substance Co-Use Patterns in Adolescents From the Fragile Families Study

The current study examined the prevalence of alcohol, cigarette, and cannabis co-use among a longitudinal cohort of youth predominately born to single-parent families. Data were drawn from wave six of the Fragile Families and Child Wellbeing Study ( N = 2976; M age = 15.6; 49% female; 53% non-Hispanic Black, 27% Hispanic, 20% White). Adolescents’ reports of their past 30-day use of alcohol, cigarettes, and cannabis were used to construct eight mutually exclusive use groups. Multinomial logistic regressions adjusting for sociodemographic factors revealed that Black adolescents were at lower relative risk of using Alcohol Only compared to White adolescents. Black males were at greater relative risk of using Cannabis Only than both White males and Black females. Finally, Hispanic males were at a marginally increased relative risk of co-using Alcohol and Cannabis compared to White males. Prevention efforts targeting Black and Hispanic males’ use of cannabis (both alone and in combination with alcohol) may be beneficial.

The relationships between marijuana use and exercise among young and middle-aged adults

As decriminalization, increased access, and decreased perception of risk spurs the popularity of medical and recreational marijuana, more information is needed on possible links between marijuana use and social determinants of health. The goal of this study was to assess the relationships between marijuana use and exercise. Data sources included the two most recent waves of the National Longitudinal Study of Adolescent to Adult Health (Wave IV, 2008-2009; N = 14,784 and Wave V, 2016-2018; N = 12,043). The exercise variables included any form of exercise/sport during the past 7 days and the number of days participating in each of 7 types of exercise/sport. Marijuana-use variables comprised any current use and frequency of use during the past 30 days. Both fixed-effects and random-effects models were estimated with numerous control variables, along with binary and count measures of exercise. Results show that, particularly for fixed-effects models, marijuana use is not significantly related to exercise, counter to conventional wisdom that marijuana users are less likely to be active. Indeed, the only significant estimates suggest a positive relationship, even among heavier users during the past 30 days. These findings are at odds with much of the existing literature, which generally shows a negative relationship between marijuana use and exercise. As additional states legalize the medicinal and recreational use of marijuana, perhaps its impact on exercise, one of the leading social determinants of health, is not necessarily a primary concern.

Driving after marijuana use among U.S. adolescents: Prevalence profiles and related behaviors

OBJECTIVES

The interplay between marijuana legislation, perceptions of risks associated with marijuana use, and marijuana-related risk behaviors is an ever changing and complex issue. Marijuana impaired driving is of concern as legalization continues to expand in the United States. While driving after using marijuana has been shown to be prevalent among adults, little research has examined the behavior in adolescents. The aim of the present study was to examine the prevalence of driving after using marijuana among U.S. adolescents, with an examination of the relationship to age of marijuana initiation and marijuana usage patterns.

METHODS

We analyzed data from the 2017 Youth Risk Behavior Survey, a nationally representative sample of high schools students in the U.S. The sample was current marijuana users, defined as past 30 day use. Driving after using marijuana was the main outcome variable, with analyses examining the association between the outcome and age of initiation and patterns of use. Prevalence ratios were obtained by modeling Poisson regression to examine factors associated with driving under the influence of marijuana.

RESULTS

Nearly half of all marijuana users reported driving after use during the past 30 days, and did not differ between males and females. Prevalence of driving after using marijuana was significantly higher among heavy users (PR = 2.8; 95% CI 2.1-3.6). A higher prevalence of driving after drinking alcohol (PR = 1.7; 95% CI 1.5-1.9) was also found among those who had driven after using marijuana.

CONCLUSIONS

Among adolescent marijuana users, the prevalence of driving after using marijuana was high. Enhanced surveillance, prevention, and control measures are necessary to mitigate the negative impacts of marijuana consumption and related behaviors.

A systematic review of neuroimaging and acute cannabis exposure in age-of-risk for psychosis

Acute exposure to cannabis has been associated with an array of cognitive alterations, increased risk for neuropsychiatric illness, and other neuropsychiatric sequelae including the emergence of acute psychotic symptoms. However, the brain alterations associating cannabis use and these behavioral and clinical phenotypes remains disputed. To this end, neuroimaging can be a powerful technique to non-invasively study the impact of cannabis exposure on brain structure and function in both humans and animal models. While chronic exposure studies provide insight into how use may be related to long-term outcomes, acute exposure may reveal interesting information regarding the immediate impact of use and abuse on brain circuits. Understanding these alterations could reveal the connection with symptom dimensions in neuropsychiatric disorders and, more specifically with psychosis. The purpose of the present review is to: 1) provide an update on the findings of pharmacological neuroimaging studies examining the effects of administered cannabinoids and 2) focus the discussion on studies that examine the sensitive window for the emergence of psychosis. Current literature indicates that cannabis exposure has varied effects on the brain, with the principal compounds in cannabis (delta-9-tetrahydrocannabinol and cannabidiol) altering activity across different brain regions. Importantly, we also discovered critical gaps in the literature, particularly regarding sex-dependent responses and long-term effects of chronic exposure. Certain networks often characterized as dysregulated in psychosis, like the default mode network and limbic system, were also impacted by THC exposure, identifying areas of particular interest for future work investigating the potential relationship between the two.

Cannabis use among Norwegian university students: Gender differences, legalization support and use intentions, risk perceptions, and use disorder

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Past year cannabis use was fairly common in a sample of Norwegian college students.

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About 6% of users possibly met criteria for use disorder, function of use frequency.

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Legalization attitudes and risk perceptions were associated with cannabis use risk.

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Intentions to use cannabis if legal were evident even among some current non-users.

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Many non-users expressed uncertainty in legalization attitudes and risk perceptions.

Aims

We explored past-year cannabis use and associated characteristics, focusing on legalization attitudes, use intentions, risk perceptions, and possible dependence among Norwegian university/college students.

Methods

We examined a nation-wide sample of Norwegian university/college students (N = 49,688; 67% female) who participated in the Students’ Health and Wellbeing Study (SHoT-study) in 2018. Participants reported past-year substance use, support for cannabis legalization, intent to use cannabis if legal, and perceived risks of weekly use. Past-year cannabis use (including use frequency) was examined in relation to these indicators. Legalization support, use intentions, and risk perceptions were examined in relation to use and gender. Potential cannabis use disorder was assessed with the Cannabis Abuse Screening Test (CAST) and examined in relation to use frequency and gender.

Findings

Past-year use was reported by 15.3% (11.8% women; 22.9% men). Majority of current users (roughly 90%) used no more than 50 times past year, and 6% (3.8% women; 8.5% men) met CAST use disorder criteria. Legalization support, use intentions, and no/low risk perceptions were significantly associated with greater odds of use, and greater use frequency among current users in both crude and adjusted models. Legalization support (23.0%), use intentions (14.0%), and perceptions of no/low risk (29.2%) were also relatively common even among current non-users, especially men. Male gender and more frequent use were associated with greater CAST scores and greater odds of use disorder.

Conclusions

Cannabis use was relatively common in this student sample. In addition to targeting frequent use, interventions may focus on cannabis-related attitudes and risk perceptions among uncertain/uninformed students.

Has Cannabis Use Among Youth Increased After Changes in Its Legal Status? A Commentary on Use of Monitoring the Future for Analyses of Changes in State Cannabis Laws

As US states move toward various forms of adult access to cannabis, there has been a great interest in measuring the impact of such changes on adolescent cannabis use. Two recent prominent analyses have used Monitoring the Future (MTF), a nationally representative survey of students, to examine the effects. We compared MTF data for California and for Washington State with other survey data on use by adolescents in those states. In both studies, findings based on MTF were different from those using other larger, state-representative surveys. The discrepancy reflects the high within-state variation in prevalence rates and the small number of schools in MTF state samples. Using the Washington Health Youth Survey, we estimate that after recreational cannabis legalization past 30-day cannabis use prevalence in grade 8 decreased by 22.0%, in grade 10 prevalence decreased by 12.7%, and no effect in grade 12. These trends are consistent with those in states without recreational cannabis laws, suggesting that legalization did not impact adolescent use prevalence. Long-term trends in MTF are consistent with other data, but year-to-year volatility in state-level series undermines the survey's suitability for evaluation of state cannabis policy changes. Survey-based analyses at the state level need to be cross-validated with findings from other data sources. When findings are disparate and methodological rigor is equivalent, analyses of data sources specifically designed to describe state-level phenomena are more credible.

Measuring Attitudes Toward Medical and Recreational Cannabis Among Older Adults in Colorado

BACKGROUND AND OBJECTIVES

Cannabis use among older adults is on the rise. Despite growing interest in the topic, there exists a paucity of standardized measures capturing cannabis-specific attitudes among older adults. Using data from a survey of older Coloradans, we create two scales that separately measure medical and recreational cannabis attitudes. We also examine how these two attitudes relate to individual-level characteristics.

RESEARCH DESIGN AND METHODS

We assess reliability using Cronbach's alpha and item-rest correlations and perform confirmatory factor analyses to test the two attitude models. We conduct a seemingly unrelated regression estimation to assess how individual characteristics predict medical and recreational cannabis attitude scores.

RESULTS

Twelve indicators combined into two valid and reliable scales. Both scales had a three-factor structure with affect, cognition and social perception as latent dimensions. For both scales, fit indices for the three-factor model were statistically superior when compared with other models. The three-factor structure for both scales was invariant across age groups. Age, physical health, and being a caregiver differentially predicted medical and recreational cannabis attitude scores.

DISCUSSION AND IMPLICATIONS

Medical and recreational cannabis attitude scales can inform the development and evaluation of tailored interventions targeting older adult attitudes that aim to influence cannabis use behaviors. These scales also enable researchers to measure cannabis-specific attitudes among older adults more accurately and parsimoniously, which in turn can facilitate a better understanding of the complex interplay between cannabis policy, use, and attitudes.

Examining Sex and Racial/Ethnic Differences in Co-use of Alcohol, Cannabis, and Cigarettes in a Community Sample of Adolescents

INTRODUCTION

Although adolescents often co-use alcohol, cigarettes, and cannabis, little is known about sex and racial/ethnic differences in the co-use of these substances. Therefore, this investigation examined sex and racial/ethnic differences in alcohol, cigarette, and cannabis co-use in a large and ethnically diverse group. Methods: Participants were drawn from a large, multi-site study of adolescents from three regions in the United States (N = 4,129; Mage=16.10 years, SD = 0.59; 51% female, 49% male; 37% Black, 37% Hispanic, 25% White). Participants were categorized into eight mutually exclusive groups based on their self-reported use of alcohol, cannabis, and cigarettes in the last 30 days. Results: Unadjusted multinomial logistic regression revealed that males were more likely than females to use cannabis-only and to co-use all three substances. Additionally, Black and Hispanic adolescents were more likely to use cannabis-only, while White adolescents were more likely than Black and Hispanic adolescents to co-use alcohol and cigarettes. After adjusting for other sociodemographic variables (age, household income, parental education, and parent marital status), males were more likely to use cannabis-only than females; White youth were more likely than Hispanic youth to use cigarettes only and co-use cigarettes and alcohol. White youth were more likely than Black youth to co-use alcohol and cigarettes and co-use all three substances. Discussion: These results indicate sex and racial/ethnic differences in substance co-use that were not explained by socioeconomic factors. Results of this work suggest potential strategies for targeted prevention efforts and underscore the importance of continued efforts to better understand patterns of alcohol and substance co-use.

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.

Marijuana Use Among Justice-Involved Youths After California Statewide Legalization, 2015-2018

Objectives. To determine the impact of California's recreational marijuana legalization on marijuana use among justice system-involved (JSI) adolescents and young adults, and to distinguish whether any changes resulted from legalization (passing the law) or from implementation of the law.Methods. We compared changes in JSI youths' marijuana use in 2 states: California (n = 504), where recreational marijuana use was recently legalized, and Pennsylvania (n = 478), where recreational use is still prohibited. Furthermore, we examined changes in marijuana use across 3 key time periods (October 2015-June 2018): before legalization, after legalization but before implementation, and after implementation.Results. California JSI youths did not demonstrate a significant increase in marijuana use after legalization (b = -0.010; P = .950) or implementation (b = -0.046; P = .846). However, in Pennsylvania, rates of marijuana use increased significantly after legalization (b = 0.602; P = .001) but not after implementation (b = 0.174; P = .533).Conclusions. Although recreational marijuana legalization was not associated with changes in marijuana use among youths in California, we observed increased rates of use in Pennsylvania after legalization in California. Recreational marijuana laws may be indirectly related to youths' marijuana use by supporting more permissive national attitudes toward marijuana.

Trends and Related Factors of Cannabis-Associated Emergency Department Visits in the United States: 2006-2014

OBJECTIVES

To examine national trends and contributing factors of cannabis-associated emergency department visits in the United States.

METHODS

This pooled serial cross-sectional study used a hierarchical multivariable analysis on emergency department visit adjusting for year, patient and hospital characteristics. We analyzed 2006 to 2014 National Emergency Department Sample data that identified cannabis-associated emergency department visits among patients aged 12 years or older (n = 265,128).

RESULTS

Cannabis-associated emergency department visits per 100,000 emergency department discharges increased monotonically (annually by 7%). As compared with privately insured patients, Medicare, and Medicaid, uninsured patients were over 40% more likely to visit emergency department. The age group 12 to 17 had the highest risk of emergency department visits and the risk monotonically declined as the age increased. Hospitals in the South region showed the highest cannabis-associated emergency department utilization, yet trends of cannabis-associated emergency department visits increased in the West region from 15.4% to 26% over time.

CONCLUSIONS

Cannabis-associated emergency department visits increase monotonically over time. Although vulnerable persons were identified, additional policy or regional factors should explore risks of emergency department visits associated with cannabis use.

[Cannabis use among the drug users with compulsory detained detoxification treatment in China]

OBJECTIVE

To explore the epidemic situation of cannabis use among drug users with compulsory detained detoxification treatment in China.

METHODS

Using the data from the Drug Abuse Population Estimation in the Key Cities of the Ministry of Public Security, we analyzed the sociodemographic characteristics and substance use of cannabis abusers with compulsory detained detoxification treatment in 55 provincial capital cities and key cities of China. Chi-square test, Fisher exact test and Kruskal-Wallis rank sum test were used to compare the prevalence of cannabis, heroin, synthetic and mixed drug use among patients with detoxification treatment, as well as the differences in polydrug use and areas among cannabis users.

RESULTS

In the study, 25 366 drug users with compulsory detained detoxification treatment were recruited, of whom 2.2% (546/25 366) used cannabis in the previous year before the treatment. The proportion of males was 83.5%, and the proportion of ethnic minorities was 41.0%. Those who received junior high school education or above accounted for 30.8%, and the unemployed accounted for 44.1%. The average age was (33.3±8.2) years, the average age of beginning drug use was (24.8±7.7) years, and the average duration between the first drug abuse and first detoxification treatment was (5.4±4.6) years. The prevalence of cannabis use was higher among those drug users who were 35-year-old and younger, ethnic minorities, employees and residents in Xinjiang. Of the cannabis users, 91.4% used polydrug, 13.6% combined with heroin alone, 42.1% combined with synthetic drugs alone and 35.7% combined with both of heroin and synthetic drugs. Of the cannabis users, 49.6% came from 3 regions: Xinjiang Uygur Autonomous Region, Jiangsu Province and Shanghai City. The cannabis users in Xinjiang had a high proportion of ethnic minorities who received junior high school education and below. Moreover, 79.6% of them combined cannabis use with heroin. The cannabis users in Jiangsu, Zhejiang and Shanghai areas had a higher proportion of ethnic Han who received better education (high school and above). Moreover, 92.7% of them combined cannabis use with methamphe-tamine.

CONCLUSION

The prevalence of cannabis use among the population with compulsory detained detoxification treatment is higher than that among drug users under surveillance, but there are obvious regional cluster effect and high possibility of polydrug abuse. Thus, it's important to strengthen the monitoring of cannabis use, to increase the control of cannabis and to formulate China's anti-cannabis policy among different population.

Peer-to-Peer Social Media as an Effective Prevention Strategy: Quasi-Experimental Evaluation

Background

Substance use by adolescents remains to be at unacceptably high levels, and there is evidence that teens’ social norms are becoming more favorable toward recreational use and perceived safety of substances such as marijuana and prescription opioids. Social media offer a low-cost, potentially high-impact approach to disseminate prevention messages.

Objective

Living the Example (LTE) is a program that trains adolescent youth ambassadors to develop and disseminate prevention messages within their own social media networks and through in-school activities. This study aimed to evaluate the effects of exposure to LTE-based social media on students in the youth ambassadors’ networks.

Methods

The George Washington (GW) University designed and implemented a quasi-experimental evaluation of the LTE program in 3 Maryland high schools. Before program launch, a sample of 826 students (wave 1) at the 3 schools, drawn from a census of freshmen enrolled in a class attended by all students at the grade level, completed a survey. A total of 584 students were surveyed at the wave 2 program midpoint and 542 at the wave 3 endpoint. The survey contained questions on drug use–related attitudes, beliefs, intentions, and behaviors, all based on validated measures. We evaluated the effects of LTE on the intended next 30-day drug use, and controlling for LTE self-reported exposure, age, and gender from waves 2 and 3 was appended into a single dataset. We first conducted ordinal logistic regressions for each drug use intention in wave 3 (ie, sell or distribute illegal drugs, smoke cigarettes, drink beer/wine/hard liquor when parents do not know about it, use marijuana, use lysergic acid diethylamide, cocaine, amphetamines or other illegal drugs, use heroin, use synthetic drugs, and use any prescription pills without a prescription) to examine the association between LTE exposure and drug use intentions. We included an interaction term for the study wave to examine intervention effects.

Results

We found a significant positive effect of LTE exposure on all 8 measured drug use intentions: sell/distribute illegal drugs; smoke cigarettes; drink beer, wine, or liquor when my parents do not know about it; use marijuana; use cocaine, amphetamines, or other illegal drug; use heroin; use synthetic drugs; use any prescription pills without a prescription (all P<.05; odds ratios ranging from 2.12 to 3.71). We also found that boys were more likely than girls to exhibit reduced drug use intentions. We also found reductions in 30-day intentions between the second and third survey waves for all 8 measured drug use variables.

Conclusions

Overall, the results are consistent with and indicate a stronger LTE effect in this study compared with a previous pilot study. LTE appears to offer a protective effect, with exposure to program messages leading to reduced/improved drug use intentions.

Cannabinoids as therapeutics for PTSD

Post-traumatic stress disorder (PTSD) is a complex disorder that involves dysregulation of multiple neurobiological systems. The traumatic stressor plays a causal role in producing psychological dysfunction and the pattern of findings suggests that the hypothalamic-pituitary-adrenal (HPA) axis, which is instrumental for stress adaptation, is critically dysfunctional in PTSD. Given the lack of understanding of the basic mechanisms and underlying pathways that cause the disorder and its heterogeneity, PTSD poses challenges for treatment. Targeting the endocannabinoid (ECB) system to treat mental disorders, and PTSD in particular, has been the focus of research and interest in recent years. The ECB system modulates multiple functions, and drugs enhancing ECB signaling have shown promise as potential therapeutic agents in stress effects and other psychiatric and medical conditions. In this review, we focus on the interaction between the ECB-HPA systems in animal models for PTSD and in patients with PTSD. We summarize evidence supporting the use of cannabinoids in preventing and treating PTSD in preclinical and clinical studies. As the HPA system plays a key role in the mediation of the stress response and the pathophysiology of PTSD, we describe preclinical studies suggesting that enhancing ECB signaling is consistent with decreasing PTSD symptoms and dysfunction of the HPA axis. Overall, we suggest that a pharmacological treatment targeted at one system (e.g., HPA) may not be very effective because of the heterogeneity of the disorder. There are abnormalities across different neurotransmitter systems in the pathophysiology of PTSD and none of these systems function uniformly among all patients with PTSD. Hence, conceptually, enhancing ECB signaling may be a more effective avenue for pharmacological treatment.

Modes of Marijuana Consumption Among Colorado High School Students Before and After the Initiation of Retail Marijuana Sales for Adults

OBJECTIVE

This study aimed to estimate the prevalence of different modes of marijuana consumption (e.g., smoking, ingesting) overall and by sociodemographic factors, marijuana-related perceptions, and other substance use among adolescents, as well as to characterize differences in the usual mode of consumption before and after the initiation of retail marijuana sales in 2014.

METHOD

Data are from the 2013 and 2015 administrations of the Healthy Kids Colorado Survey, a cross-sectional, school-based survey. We included 9th-12th grade students who reported past-30-day marijuana use in 2013 (n = 2,792; 44.8% female) or 2015 (n = 1,664; 48.9% female). We estimated the prevalence of any past-month use of each mode in 2015 and usual mode of consumption the past month in both years. We tested differences by year, sociodemographics, marijuana-related perceptions, and other substance use using Rao-Scott chi-square tests and multivariable logistic regression.

RESULTS

The prevalence of past-month marijuana use was 20.7% in both years. In 2015, 39.8% of students reported using multiple modes in the past month. Use of any mode other than smoking and use of multiple modes differed by sociodemographics, marijuana-related perceptions, and other substance use. Smoking remained the most common usual mode in 2015. The prevalence of usually ingesting significantly decreased from 4.7% to 2.1% between years, whereas "other mode(s)" significantly increased from 4.0% to 6.0%.

CONCLUSIONS

The use of multiple modes of marijuana consumption was prevalent among adolescents in Colorado. The usual mode of consumption changed in years before and after the implementation of retail marijuana sales, suggesting the need for continued surveillance.

The Effect of Medical Marijuana Laws on Marijuana-Related Attitude and Perception Among US Adolescents and Young Adults

Marijuana liberalization policies are gaining momentum in the USA, coupled with limited federal interference and growing dispensary industry. This evolving regulatory landscape underscores the importance of understanding the attitudinal/perceptual pathways from marijuana policy to marijuana use behavior, especially for adolescents and young adults. Our study uses the restricted-access National Survey on Drug Use and Health (NSDUH) 2004-2012 data and a difference-in-differences design to compare the pre-policy, post-policy changes in marijuana-related attitude/perception between adolescents and young adults from ten states that implemented medical marijuana laws during the study period and those from the remaining states. We examined four attitudinal/perception pathways that may play a role in adolescent and young adult marijuana use behavior, including (1) perceived availability of marijuana, (2) perceived acceptance of marijuana use, (3) perceived wrongfulness of recreational marijuana use, and (4) perceived harmfulness of marijuana use. We found that state implementation of medical marijuana laws between 2004 and 2012 was associated with a 4.72% point increase (95% CI 0.15, 9.28) in the probability that young adults perceived no/low health risk related to marijuana use. Medical marijuana law implementation is also associated with a 0.37% point decrease (95% CI - 0.72, - 0.03) in the probability that adolescents perceived parental acceptance of marijuana use. As more states permit medical marijuana use, marijuana-related attitude/perception need to be closely monitored, especially perceived harmfulness. The physical and psychological effects of marijuana use should be carefully investigated and clearly conveyed to the public.

Recreational Marijuana Availability in Oregon and Use Among Adolescents

INTRODUCTION

This study investigated whether legalization of recreational marijuana sales and retail availability of marijuana in Oregon counties were associated with higher levels of marijuana use and related beliefs among adolescents.

METHODS

Biennial data for 6th, 8th, and 11th graders from the 2010-2018 Student Wellness Survey in 35 Oregon counties (n=247,403) were analyzed in 2019 to assess changes in past 30-day marijuana use and beliefs (e.g., perceived availability of marijuana) in counties that allowed recreational marijuana sales in unincorporated areas beginning in October 2015 versus counties that did not. Analyses were also conducted with 2016 and 2018 Student Wellness Survey data (n=101,419) to determine whether the association between allowing recreational marijuana sales and marijuana use could be accounted for by retail marijuana outlet density and beliefs.

RESULTS

Higher rates of past 30-day marijuana use and more favorable beliefs were observed in counties that allow recreational marijuana sales in unincorporated areas, both before and after legalization of recreational sales in 2015. The prevalence of past 30-day marijuana use increased, relative to the downward secular trend, after legalization both in counties that did and did not allow recreational marijuana sales. There were parallel changes in beliefs favorable to marijuana use. Analyses with 2016 and 2018 Student Wellness Survey data suggested that the association between allowing recreational marijuana sales and past 30-day marijuana use could be accounted for by retail marijuana outlet density and beliefs.

CONCLUSIONS

Legalization and greater retail availability of recreational marijuana are positively associated with marijuana use among adolescents.

Trends in Cannabis Treatment Admissions in Adolescents/Young Adults: Analysis of TEDS-A 1992 to 2016

OBJECTIVES

This study aims to evaluate changes in cannabis use patterns, referral sources, and admissions in adolescents and young adults (YAs). As the United States increasingly moves toward liberalization of cannabis laws, it is critical to have baseline information of use patterns in this population.

METHODS

Data were drawn from Treatment Episode Data Set-Admissions (TEDS-A) for adolescents (12-17 years) and young adults (18-24 years) entering treatment from 1992 to 2016 for primary cannabis use (N = 3,794,213). Rao-Scott chi-square tests were used to test for significant changes in proportions of individuals admitted to treatment for primary cannabis use and between 4-year increments from 1992 to 2016 (N = 1,052,724). Logistic regression assessed odds of admissions for primary cannabis use versus other substances.

RESULTS

Treatment admissions for cannabis among adolescents/YAs rose 3-fold from 1992 (49,996) to 1996 (125,858). The majority of referrals came from the criminal justice system (56%). Cannabis is increasingly the sole substance of use, with polysubstance use decreasing from 89% in 1992 to 59% in 2016. While alcohol-related treatment admissions were most common in 1992, admissions for treatment of cannabis use (followed by heroin and alcohol) were highest (38%) by 2016. Being an adolescent (odds ratio [OR] 3.1, 95% confidence interval [CI] 3.1-3.2), non-Hispanic black (OR 6.2, 95% CI 6.2-6.3), male (female OR 0.6, 95% CI 0.6-0.6) with co-occurring alcohol use (OR 25.9, 95% CI 25.7-26.1) was associated with admission for treatment of primary cannabis use as compared with other substances.

CONCLUSIONS

Public health efforts will be needed to ensure ongoing access and referral to treatment as the legal status of cannabis continues to change. Prevention and treatment efforts should target co-occurring alcohol and cannabis use.

Beliefs about cannabis at the time of legalization in Canada: results from a general population survey

Aims

Cannabis became a legally available drug in Canada in October of 2018. The objective of this study was to examine beliefs about cannabis use at the time of legalization among past year cannabis users, those who had used cannabis but not in the last year, and people who had never used cannabis.

Design and methods

A survey of 813 participants, 18 years and over, and identified using random digit dialing methods, was made of the Canadian general population. Among other items, participants were asked a series of questions about their beliefs regarding cannabis use and recovery.

Results

Compared to never and ever users, participants who used cannabis in the last year regarded cannabis as less of a societal problem (mean [SD] past year use = 3.8 [2.4] versus 6.4 [2.6] and 6.0 [2.4] respectively, p = .001), than people were less likely to become addicted to cannabis if they tried it (past year use = 13.3% versus 48.3% and 25.1%, p = .001), and a larger proportion believed that recovery from cannabis without treatment was likely (past year use = 40.8% versus 14.2% and 19.3%, p = .001). All groups were equally positive of the chances of recovering from cannabis addiction with treatment (p = .72).

Discussion and conclusion

Beliefs about cannabis use vary substantially between those who have used the drug in the past year and those who have not. Replication of the survey at a later date is merited in order to assess the ways in which beliefs about cannabis evolve after an extended period of cannabis being available as a legal drug.

Beyond the Bud: Emerging Methods of Cannabis Consumption for Youth

Cannabis continues to be the most widely used illicit substance among youth, as many teens view the risks of cannabis consumption to be low. With cannabis laws becoming lax and dispensaries becoming more prevalent throughout the United States, highly concentrated Δ-9-tetrahydrocannibinol (THC) is becoming readily available. This article examines the available literature on consumption of concentrated THC, focusing on potential consequences of concentrate use among youth. Various methods for consuming concentrated THC, including ingestion of edibles, vaping, and dabbing, are discussed, along with associated risks of each consumption method. Recommendations for health professionals are provided.

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.

Employment and Marijuana Use Among Washington State Adolescents Before and After Legalization of Retail Marijuana

PURPOSE

The purpose of the study was to describe associations between employment and marijuana use among adolescents 2 years before passage of 2012 ballot initiative and 2 years after the implementation of retail recreational marijuana sales took place in Washington.

METHODS

We used 2010 and 2016 data from Washington's statewide school-based Healthy Youth Survey, which is completed by more than 76,000 youth annually and representative of 8th, 10th, and 12th graders in public schools. We used "difference-in-differences" regression to estimate the odds of current, past 30-day marijuana use by working status and hours worked per week compared with nonworking youth.

RESULTS

Working adolescents in all grades had higher prevalence of recent marijuana use compared with nonworking adolescents. Youth working in formal settings, such as retail and service sectors, were more likely to use marijuana than nonworking and youth working in informal settings, such as babysitting. Between 2010 and 2016, marijuana use decreased significantly among working and nonworking 8th and 10th graders. Among working 12th graders, marijuana use increased significantly over time relative to nonworking youth (adjusted odds ratio: 1.34, 95% confidence interval: 1.22-1.48). Associations were stronger for youth who worked more hours per week.

CONCLUSIONS

Working youth were more likely to use marijuana before and after Washington's legalization of retail marijuana. Legalization was associated with increases in marijuana use specifically among 12th-grade working youth. States legalizing marijuana may consider implementing interventions to support healthy behaviors among working youth.

Perceived harmfulness of various alcohol- and cannabis use modes: Secular trends, differences, and associations with actual substance use behaviors among Norwegian adolescents, 2007-2015

BACKGROUND

How youth perceive harmfulness of risk behaviors such as substance use relates to their engagement in those behaviors. Yet, little is known about how different substance use modes (i.e., variations in amounts and use frequencies) are perceived. We investigated how adolescent perceptions of harmfulness of various alcohol- and cannabis use modes changed over time, compared to one another, and related to actual substance use behaviors.

METHODS

We examined nationally-representative repeated cross-sectional samples of 16-year olds in Norway, assessed in 2007, 2011, and 2015 (N_Total = 9296) as part of the European School Survey Project on Alcohol and Other Drugs (ESPAD). Adolescents reported their: 1) lifetime alcohol- and cannabis use, and 2) perceived harmfulness of various alcohol- and cannabis use modes.

RESULTS

Prevalence estimates for perceived harmfulness: 1) remained high and stable, or increased for alcohol use modes, and 2) declined for all cannabis use modes (i.e., using 1-2 times, occasionally, and regularly) since 2007-cohort. High quantity daily drinking was more commonly perceived as harmful than minimal or occasional cannabis use. Even though culturally-relevant use modes (i.e., weekend heavy drinking and experimental cannabis use) were not most commonly endorsed as harmful, only perceptions of those use modes as harmful were inversely associated with actual substance use.

CONCLUSIONS

How adolescents from Norway perceived harmfulness of alcohol- and cannabis use depended on the specific substance, its use modes, and secular cohort. Perceived harmfulness was associated with measures of actual substance use predominantly along the culturally- and adolescent-relevant modes of use.

Factors associated with cannabis use change in youth: Evidence from the COMPASS study

INTRODUCTION

Harmful effects of cannabis use in youth scale with frequency. In the context of approaching legalization in Canada, understanding the distinctions between youth who change and who maintain their cannabis use is essential for designing interventions and policy. A substantial number of characteristics may play a role. This study assessed whether and how youth who change their cannabis use differ from those who do not.

METHODS

Cannabis use was reported by 8375 Canadian high school students participating in the COMPASS study. GEE multiple logistic regressions were then used to establish impact of 13 baseline demographic and behavioural exposure variables on the likelihood of membership in four frequency change groups at follow-up a year later: reduction, cessation, escalation, and maintenance.

RESULTS

Groups were found to differ in several ways. Cessation group members (19.4% of users) were less likely to binge drink (OR 0.82), vape (OR 0.82), or attend class without completing homework (OR 0.72) than maintainers. Students who reduced their use (14.6% of users) were more likely to binge drink (OR 1.36), smoke (OR 1.20), and skip class (OR 1.21). Those who escalated (29.5% of users) were more likely to be male (OR 1.35) and to vape (OR 1.22).

CONCLUSIONS

Students who change their cannabis use differ in several demographic and behavioural characteristics. The results raise further concerns about the impact of e-cigarettes and the role of poly-substance use in high-risk trajectories. Distinct classes of cannabis users, essential for policy and intervention development, can be identified in high school populations.

A quasi-experimental evaluation of marijuana policies and youth marijuana use

BACKGROUND

Marijuana use carries risks for adolescents' well-being, making it essential to evaluate effects of recent marijuana policies.

OBJECTIVES

This study sought to delineate associations between state-level shifts in decriminalization and medical marijuana laws (MML) and adolescent marijuana use.

METHODS

Using data on 861,082 adolescents (14 to 18+ years; 51% female) drawn from 1999 to 2015 state Youth Risk Behavior Surveys (YRBS), difference-in-differences models assessed how decriminalization and MML policy enactment were associated with adolescent marijuana use, controlling for tobacco and alcohol policy shifts, adolescent characteristics, and state and year trends.

RESULTS

MML enactment was associated with small significant reductions (OR = 0.911, 95% CI [0.850, 0.975]) of 1.1 percentage points in current marijuana use, with larger significant declines for male, Black, and Hispanic (2.7-3.9 percentage points) adolescents. Effects of MML increased significantly with each year of exposure (OR = 0.980, 95% CI [0.968, 0.992]). In contrast, decriminalization was not associated with significant shifts in use for the sample as a whole, but predicted significant declines in marijuana use among 14-year olds and those of Hispanic and other ancestry (1.7-4.4 percentage points), and significant increases among white adolescents (1.6 percentage points). Neither policy was significantly associated with heavy marijuana use or the frequency of use, suggesting that heavy users may be impervious to such policy signals.

CONCLUSION

As the first study to concurrently assess unique effects of multiple marijuana policies, results assuage concerns over potential detrimental effects of more liberal marijuana policies on youth use.

Adolescent Marijuana Use, Marijuana-Related Perceptions, and Use of Other Substances Before and After Initiation of Retail Marijuana Sales in Colorado (2013-2015)

Due to the recentness of changes to marijuana policies in a number of states, the effect on adolescent use and perceptions is not yet well understood. This study examines change in adolescent marijuana use and related perceptions in Colorado, before and after the implementation of legal commercial sale of recreational marijuana for adults starting on January 1, 2014. The data are from a repeated cross-sectional survey of a representative sample of Colorado high school students, with separately drawn samples surveyed in fall 2013 (prior to implementation) and fall 2015 (18 months after implementation). We examined change in the prevalence of adolescent marijuana use, measured by lifetime use, past 30-day use, frequent use, and use on school property. To consider the possibility of heterogeneity in the change in marijuana use, we examined change in past 30-day marijuana use by demographic characteristics (sex, grade, race/ethnicity), school characteristics (poverty, percent minority), urbanicity of the school district, and whether the city or county permitted retail marijuana stores. There was an absence of significant effects for change in lifetime or past 30-day marijuana use. Among those reporting past 30-day use, frequent use and use on school property declined. There was a significant decline in the perceived harm associated with marijuana use, but we did not find a significant effect for perceived wrongfulness, perceived ease of access, or perceived parental disapproval. We did not find significant variability in past 30-day use by demographic characteristics or by school and community factors from 2013 to 2015. We did not find a significant effect associated with the introduction of legal sales of recreational marijuana to adults in Colorado on adolescent (illegal) use, but ongoing monitoring is warranted, including consideration of heterogeneity in the effects of marijuana policies.

How and why have attitudes about cannabis legalization changed so much?

Since the late 1990s public opinion about cannabis legalization has become drastically more liberal, and some states have begun to legalize cannabis for recreational use. Why have attitudes changed so much? Prior research has considered a few of the reasons for this change, but this is the first comprehensive and empirically-based study to consider the wide range of potential causes for how and why this happened. We use data from the General Social Survey, National Study of Drug Use and Health, and word searches from the New York Times. We find that attitudes largely liberalized via intracohort changes. Most Americans developed more liberal views, regardless of their race and ethnicity, gender, education, religious or political affiliation, or religious engagement. Changes in cannabis use have had minimal effects on attitudes, and legalization of cannabis has not prompted attitude change in neighboring states. As to root causes, evidence suggests that a decrease in religious affiliation, a decline in punitiveness, and a shift in media framing all contributed to changing attitudes.

Poly-use of cannabis and other substances among juvenile-justice involved youth: variations in psychological and substance-related problems by typology

BACKGROUND

Adolescent cannabis use is associated with increased risk for psychological problems, with evidence for more severe problems among youth who use cannabis in combination with other substances (i.e., polysubstance use). Juvenile offenders engage in both cannabis use and polysubstance use at higher rates than the general adolescent population. Yet, limited research has examined the relationship between cannabis poly-use (e.g., cannabis and alcohol use) and functional or psychological problems among juvenile offenders.

OBJECTIVES

The current study addresses this gap by examining the association of polysubstance use of cannabis compared to cannabis only use with cognitive functioning, psychological distress, and substance-related problems among juvenile detainees.

METHODS

Participants were 238 detained youth ages 12-18 (80.4 % male, 77.3% non-White) who completed assessments of substance use, intellectual functioning, psychological symptoms, and substance-related problems. Youth were also assessed by a clinical psychologist for substance use disorder.

RESULTS

Four cannabis-use typologies were identified; cannabis and alcohol use was the largest class, followed by cannabis only use, cannabis, alcohol and other drug use, then cannabis and other drug use. Polysubstance use was associated with lower scores on measures of intellectual functioning, more externalizing and internalizing symptomology, and more substance-related problems relative to cannabis only use. However, the relationship between polysubstance use and problems varied by typology.

CONCLUSIONS

Findings suggest that justice-involved youth engaged in polysubstance use may be at greater need for concurrent academic, affective, and behavioral support in their rehabilitation and transition back to the community.

Reasons High School Students Use Marijuana: Prevalence and Correlations With Use Across Four Decades

OBJECTIVE

Changes in the legality and prevalence of marijuana raise questions about whether adolescents' reasons for using marijuana and associations between reasons for use and recent marijuana use have changed historically.

METHOD

Using nationally representative data from Monitoring the Future for 1976-2016 (N = 39,964; 47.6% female), we examined changes in self-reported reasons for marijuana use and in the associations between reasons for use and past-30-day marijuana use among 12th graders who used marijuana in the past 12 months.

RESULTS

Time-varying effect modeling showed variation in reasons for use among adolescent past-year marijuana users from 1976 to 2016. Social/recreational reasons for marijuana use (i.e., Boredom, Feel Good/Get High, Experiment, Fit In) generally declined in prevalence; the exception was Good Time, which remained quite stable. Prevalence of coping with negative affect reasons (i.e., Anger/Frustration, Escape Problems, Relax, Get Through Day) approximately doubled across 40 years. Over time, social/recreational reasons were consistently associated with greater odds (i.e., Boredom, Feel Good/Get High, Good Time) or lower odds (i.e., Experiment, Fit In) of recent marijuana use. Coping with negative affect reasons, drug effect reasons, and compulsive use were consistently associated with greater odds of recent use.

CONCLUSIONS

The most common reasons for marijuana use among high school students have shifted markedly in 40 years, with particular increases for coping-related reasons. However, reasons for use remain significant, stable predictors of use. This suggests a move toward riskier (coping-related) use but supports the continued salience of motivation-based approaches for prevention and intervention.