Changes in alcohol and cigarette consumption in response to medical and recreational cannabis legalization: Evidence from U.S. state tax receipt data

Effectiveness of Cannabidiol to Manage Chronic Pain: A Systematic Review

OBJECTIVES

Cannabidiol (CBD), a component in Cannabis, is used to treat seizures, anxiety, and pain. Little is known about how effectively CBD works in managing chronic pain, a condition characterized by discomfort that persists beyond 3-6 months or beyond expected normal healing. Therefore, this systematic review aimed to synthesize evidence on the effectiveness of CBD in chronic pain management.

DESIGN

A systematic review of literature utilizing PRISMA 2020 guidelines.

DATA SOURCES

PubMed/MEDLINE, Web of Science, CINAHL, Academic Search Complete, PsycArticles, PsycINFO, SocINDEX, and CENTRAL. The gray literature search was performed through the World Health Organization, the Centers for Disease Control and Prevention, and the European Centre for Disease Prevention and Control.

REVIEW/ANALYSIS METHODS

We searched eight databases and gray literature for relevant studies until August 30, 2022. We gathered original research articles with various study designs published in English that looked at patients who used CBD to manage their chronic pain. Two authors assessed the risk of bias and certainty of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. We used narrative synthesis to analyze the results.

RESULTS

We included 15 studies among 1,516 identified articles. The majority of the studies indicated pain reduction ranging from 42% - 66% with CBD alone and CBD with Tetrahydrocannabinol. Three studies showed no significant improvement in reducing pain, and one had mixed findings in pain control. The included studies had various methods of measuring pain reduction, mostly through self-reporting and scales such as visual analog scales and verbal numerical scales, among others.

CONCLUSION

CBD may be useful in treating chronic pain. Findings should be interpreted with caution due to the small number of included studies and heterogeneity brought about by different study designs and outcome measures. More studies with robust study designs are warranted to evaluate CBD's effectiveness in treating chronic pain.

Association between non-medical cannabis legalization and alcohol sales: Quasi-experimental evidence from Canada

BACKGROUND

There is increasing interest in understanding the impact of non-medical cannabis legalization on use of other substances, especially alcohol. Evidence on whether cannabis is a substitute or complement for alcohol is both mixed and limited. This study provides the first quasi-experimental evidence on the impact of Canada's legalization of non-medical cannabis on beer and spirits sales.

METHODS

We used the interrupted time series design and monthly data on beer sales between January 2012 and February 2020 and spirits sales between January 2016 and February 2020 across Canada to investigate changes in beer and spirits sales following Canada's cannabis legalization in October 2018. We examined changes in total sales, nationally and in individual provinces, as well as changes in sales of bottled, canned and kegged beer.

RESULTS

Canada-wide beer sales fell by 96 hectoliters per 100,000 population (p=0.011) immediately after non-medical cannabis legalization and by 4 hectoliters per 100,000 population (p>0.05) each month thereafter for an average monthly reduction of 136 hectoliters per 100,000 population (p<0.001) post-legalization. However, the legalization was associated with no change in spirits sales. Beer sales reduced in all provinces except the Atlantic provinces. By beer type, the legalization was associated with declines in sales of canned and kegged beer but there was no reduction in sales of bottled beer.

CONCLUSIONS

Non-medical cannabis legalization was associated with a decline in beer sales in Canada, suggesting substitution of non-medical cannabis for beer. However, there was no change in spirits sales following the legalization.

Immigration status-related exclusive e-cigarette use and cannabis use and their dual use disparities associated with mental health disorder symptoms

INTRODUCTION

E-cigarette and cannabis use has been linked to various health risks, including respiratory and cardiovascular conditions. Yet, extant knowledge about the risk factors for exclusive and dual use of e-cigarettes and cannabis is limited, especially among immigrants. We examined exclusive e-cigarette and cannabis use and their dual use associated with mental health disorders among immigrants and U.S.-born.

METHODS

We analyzed national cross-sectional data collected between May 13, 2021, and January 9, 2022, among adults aged >18 years (n= 4766) living in U.S. Multinomial logistic regression analyses were conducted to model the associations of exclusivity and dual-use (reference group= non-use) with anxiety/depression.

RESULTS

The dual-use prevalence was higher than exclusive e-cigarette and cannabis use, especially among U.S.-born (dual use= 14.79% vs. cannabis use= 13.53% vs. e-cigarette use= 7.11%) compared to immigrants (dual use= 8.23% vs. cannabis use= 5.03% vs. e-cigarette use= 6.31%). Immigrants had lower risks of exclusive cannabis and dual use compared to U.S.-born. Anxiety/depression was associated with higher risks of exclusive cannabis use and dual use across immigration status, but was associated with exclusive e-cigarette use among only immigrants. While effect sizes of dual-use associated with anxiety/depression were higher among U.S.-born, the effect sizes of exclusive e-cigarette and cannabis use associated with anxiety/depression were higher among immigrants.

CONCLUSIONS

The findings revealed significant mental health risks for e-cigarette, cannabis, and their dual use among immigrants and U.S.-born, especially among U.S.-born. These findings highlight the need for public health research and interventions to consider immigration status-related disparities in substance use.

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.

The Stage-Based Model of Addiction-Using Drosophila to Investigate Alcohol and Psychostimulant Responses

Addiction is a progressive and complex disease that encompasses a wide range of disorders and symptoms, including substance use disorder (SUD), for which there are few therapeutic treatments. SUD is the uncontrolled and chronic use of substances despite the negative consequences resulting from this use. The progressive nature of addiction is organized into a testable framework, the neurobiological stage-based model, that includes three behavioral stages: (1) binge/intoxication, (2) withdrawal/negative affect, and (3) preoccupation/anticipation. Human studies offer limited opportunities for mechanistic insights into these; therefore, model organisms, like Drosophila melanogaster, are necessary for understanding SUD. Drosophila is a powerful model organism that displays a variety of SUD-like behaviors consistent with human and mammalian substance use, making flies a great candidate to study mechanisms of behavior. Additionally, there are an abundance of genetic tools like the GAL4/UAS and CRISPR/Cas9 systems that can be used to gain insight into the molecular mechanisms underlying the endophenotypes of the three-stage model. This review uses the three-stage framework and discusses how easily testable endophenotypes have been examined with experiments using Drosophila, and it outlines their potential for investigating other endophenotypes.

Have recreational marijuana laws undermined public health progress on adult tobacco use?

Public health experts caution that legalization of recreational marijuana may normalize smoking and undermine the decades-long achievements of tobacco control policy. However, very little is known about the impact of recreational marijuana laws (RMLs) on adult tobacco use. Using newly available data from the Population Assessment of Tobacco and Health (PATH) and dynamic difference-in-differences and discrete-time hazard approaches, we find that RML adoption increases prior-month marijuana use among adults ages 18-and-older by 2-percentage-points, driven by an increase in marijuana initiation among prior non-users. However, this increase in adult marijuana use does not extend to tobacco use. Rather, we find that RML adoption is associated with a lagged reduction in electronic nicotine delivery systems (ENDS) use, consistent with the hypothesis that ENDS and marijuana are substitutes. Moreover, auxiliary analyses from the National Survey on Drug Use and Health (NSDUH) show that RML adoption is associated with a reduction in adult cigarette smoking. We conclude that RMLs may generate tobacco-related health benefits.

Behavioral economic relationship between cannabis and cigarettes: Evidence from hypothetical purchase tasks

BACKGROUND

In the United States (U.S), cannabis policies have been increasingly liberalized whereas tobacco policies have been increasingly stringent. Given the high prevalence of cannabis and tobacco dual use, there are concerns that a policy regulating one substance may unintendedly influence the other. This study examined the responsiveness of the demand for cannabis joints and cigarettes when price varied.

METHODS

The study included 338 adult participants (21+) who used both cannabis and tobacco and lived in one of the U.S. states with recreational cannabis legalized by the time of interview in 2019. They completed hypothetical purchase tasks to indicate the quantity desired of cannabis joints and cigarette packs 1) when only one substance was available with escalating prices and 2) when both substances were concurrently available with escalating prices of cannabis joints and a fixed price of cigarette packs. We estimated 1) the own-price elasticity of demand for each substance using nonlinear exponential demand model, and 2) the cross-price elasticity of demand at aggregate level using nonlinear exponential demand model and at individual level using log-linear demand model.

RESULTS

The estimates for the rate of change of own-price elasticity (α) were 0.0011 (SE = 0.000039, p < 0.001) for cannabis joints and 0.00095 (SE = 0.000037, p < 0.001) for cigarette packs. The aggregate-level estimates of cross-price elasticity (I = 13.032, SE = 0.34, p < 0.001; β = 0.0029, SE = 0.0021, p > 0.05) suggest an independent relationship between the two substances. At individual level, 78.70% of the participants treated the two substances as independent, 17.46% as complements, and 3.85% as substitutes.

CONCLUSIONS

For most adults who used both cannabis and tobacco in the U.S., cannabis joints and cigarettes had an independent relationship. Policies regulating the price of cannabis may not have large unintended consequences on cigarette use.

The clouded debate: A systematic review of comparative longitudinal studies examining the impact of recreational cannabis legalization on key public health outcomes

Background

Ineffective cannabis regulatory frameworks such as prohibition have sparked interest in alternative solutions to reduce individual and societal harms. While it has been suggested that the recreational legalization process has yielded early successes, the relatively recent implementation of the novel policies has provided a modest time frame for a truly thorough establishment and assessment of key population-level indicators. The following systematic review focuses on identifying the downstream public health sequelae of cannabis legalization policies, including parameters such as cannabis consumption rates, hospitalization rates, vehicular accidents and fatalities, criminal activity, and suicidal behaviors, as well as other substance use trends.

Methods

An exhaustive search of the MEDLINE and Google Scholar databases were performed to identify high-quality (1) longitudinal studies, which (2) compared key public health outcomes between regions which had and had not implemented recreational cannabis legalization (RML) policies, (3) using distinct databases and/or time frames. Thirty-two original research articles were retained for review.

Results

Adult past-month cannabis consumption (26+ years) seems to have significantly increased following RML, whereas young adult (18-26 years) and adolescent (12-17 years) populations do not show a significant rise in past-month cannabis use. RML shows preliminary trends in increasing service use (such as hospitalizations, emergency department visits, or poisonings) or vehicular traffic fatalities. Preliminary evidence suggests that RML is related to potential increases in serious/violent crimes, and heterogeneous effects on suicidal behaviors. While the research does not illustrate that RML is linked to changing consumptions patterns of cigarette, stimulant, or opioid use, alcohol use may be on the rise, and opioid prescribing patterns are shown to be significantly correlated with RML.

Conclusion

The current data supports the notion that RML is correlated with altered cannabis consumption in adults, potentially increased criminal activity, and a decline in opioid quantities and prescriptions provided to patients. Future work should address additional knowledge gaps for vulnerable populations, such as individuals with mental health problems or persons consuming cannabis frequently/at higher THC doses. The effects of varying legalization models should also be evaluated for their potentially differing impacts on population-level outcomes.

The Genetically Informed Neurobiology of Addiction (GINA) model

Addictions are heritable and unfold dynamically across the lifespan. One prominent neurobiological theory proposes that substance-induced changes in neural circuitry promote the progression of addiction. Genome-wide association studies have begun to characterize the polygenic architecture undergirding addiction liability and revealed that genetic loci associated with risk can be divided into those associated with a general broad-spectrum liability to addiction and those associated with drug-specific addiction risk. In this Perspective, we integrate these genomic findings with our current understanding of the neurobiology of addiction to propose a new Genetically Informed Neurobiology of Addiction (GINA) model.

Association of Recreational Cannabis Legalization With Alcohol Use Among Adults in the US, 2010 to 2019

Importance

In the US, cannabis use has nearly doubled during the past decade, in part because states have implemented recreational cannabis laws (RCLs). However, it is unclear how legalization of adult-use cannabis may affect alcohol consumption.

Objective

To estimate the association between implementation of state RCLs and alcohol use among adults in the US.

Design, Settings, and Participants

This was a cross-sectional study of 4.2 million individuals who responded to the Behavioral Risk Factor Surveillance System in 2010 to 2019. A difference-in-differences approach with demographic and policy controls was used to estimate the association between RCLs and alcohol use, overall and by age, sex, race and ethnicity, and educational level. Data analyses were performed from June 2021 to March 2022.

Exposures

States with RCLs, as reported by the RAND-University of Southern California Schaeffer Opioid Policy Tools and Information Center.

Main Outcomes and Measures

Past-month alcohol use, binge drinking, and heavy drinking.

Results

Of 4.2 million respondents (median age group, 50-64 years; 2 476 984 [51.7%] women; 2 978 467 [58.3%] non-Hispanic White individuals) in 2010 through 2019, 321 921 individuals lived in state-years with recreational cannabis laws. Recreational cannabis laws were associated with a 0.9 percentage point (95% CI, 0.1-1.7; P = .02) increase in any alcohol drinking but were not significantly associated with binge or heavy drinking. Increases in any alcohol use were primarily among younger adults (18-24 years) and men, as well as among non-Hispanic White respondents and those without any college education. A 1.4 percentage point increase (95% CI, 0.4-2.3; P = .006) in binge drinking was also observed among men, although this association diminished over time.

Conclusions and Relevance

This cross-sectional study and difference-in-differences analysis found that recreational cannabis laws in the US may be associated with increased alcohol use, primarily among younger adults and men.

Trends in Alcohol, Cigarette, E-Cigarette, and Nonprescribed Pain Reliever Use Among Young Adults in Washington State After Legalization of Nonmedical Cannabis

PURPOSE

Liberalization of cannabis laws may be accompanied by changes in the use of substances other than cannabis and changes in associations of cannabis use with other types of substance use. This study assessed (1) trends in alcohol, nicotine, and nonprescribed pain reliever use and (2) changes in associations of cannabis use with these other substances among young adults in Washington State after nonmedical cannabis legalization.

METHODS

Regression models stratified by age (18-20 vs. 21-25) were used to analyze six annual waves of cross-sectional survey data from a statewide sample from 2014 through 2019 (N = 12,694).

RESULTS

Prevalence of past-month alcohol use, heavy episodic drinking (HED), and cigarette use and prevalence of past-year pain reliever misuse decreased, while the prevalence of past-month e-cigarette use increased since 2016 (the first year assessed). Across years and age groups, the prevalence of substance use other than cannabis was higher among occasional and frequent cannabis users compared to cannabis nonusers. However, associations between both occasional (1-19 days in the prior month) and frequent (20+ days) cannabis use and pain reliever misuse and between frequent cannabis use and HED weakened over time among individuals ages 21-25.

DISCUSSION

Contrary to concerns about spillover effects, implementation of legalized nonmedical cannabis coincided with decreases in alcohol and cigarette use and pain reliever misuse. The weakening association of cannabis use with the use of other substances among individuals ages 21-25 requires further research but may suggest increased importance of cannabis-specific prevention and treatment efforts.

A difference-in-difference approach to examining the impact of cannabis legalization on disparities in the use of cigarettes and cannabis in the United States, 2004-17

AIMS

To estimate the impact of recreational and medical cannabis laws (RCL, MCL) on the use of cannabis and cigarettes in the United States.

DESIGN

A difference-in-difference approach was applied to data from the 2004-17 National Survey on Drug Use and Health (NSDUH).

SETTING

United States.

PARTICIPANTS

Nationally representative cross-sectional survey of Americans aged 12 years and older (combined analytical sample for 2004-17, n = 783 663).

MEASUREMENTS

Data on past-month use of (1) cigarettes and (2) cannabis were used to classify respondents into four groups: cigarette and cannabis co-use, cigarette-only use, cannabis-only use or no cigarette or cannabis use. State of residence was measured by self-report. MCL/RCL status came from state government websites.

FINDINGS

Difference-in-difference analyses suggest that MCL was associated with an increase in cigarette-cannabis co-use overall [adjusted odds ratio (aOR) = 1.09; 95% confidence interval (CI) = 1.02-1.16], with the greatest increases among those aged 50 years and above (aOR = 1.60; CI = 1.39-1.84), married (aOR = 1.19; CI = 1.07-1.31), non-Hispanic (NH) black (aOR = 1.14; CI = 1.02-1.07) and with a college degree or above (aOR = 1.15; CI = 1.06-1.24). MCL was associated with increases in cigarette-only use among those aged 50 years and above (aOR = 1.07; CI = 1.01-1.14) and NH black (aOR = 1.16; CI = 1.06-1.27) and increases in cannabis-only use among those aged 50 years and above (aOR = 1.24; CI = 1.07-1.44) and widowed/divorced/separated (aOR = 1.18; CI = 1.01-1.37). RCL was associated with an increase in cannabis-only use overall (aOR = 1.21; 95% CI = 1.09-1.34), a decline in cigarette-only use overall (aOR = 0.89; 95% CI = 0.81-0.97) and increases in co-use among those who were married (aOR = 1.24; CI = 1.02-1.50) and aged 50 years and above (aOR = 1.37; CI = 1.03-1.84).

CONCLUSIONS

Recreational and medical cannabis legalization have had a varying impact on the use, and co-use, of cannabis and cigarettes in the United States.

Relationships of Cannabis Policy Liberalization With Alcohol Use and Co-Use With Cannabis: A Narrative Review

PURPOSE

The liberalization of cannabis policies has the potential to affect the use of other substances and the harms from using them, particularly alcohol. Although a previous review of this literature found conflicting results regarding the relationship between cannabis policy and alcohol-related outcomes, cannabis policies have continued to evolve rapidly in the years since that review.

SEARCH METHODS

The authors conducted a narrative review of studies published between January 1, 2015, and December 31, 2020, that assessed the effects of cannabis policies on the use of alcohol in the United States or Canada.

SEARCH RESULTS

The initial search identified 3,446 unique monographs. Of these, 23 met all inclusion criteria and were included in the review, and five captured simultaneous or concurrent use of alcohol and cannabis.

DISCUSSION AND CONCLUSIONS

Associations between cannabis policy liberalization and alcohol use, alcohol-related outcomes, and the co-use of alcohol and cannabis were inconclusive, with studies finding positive associations, no associations, and negative associations. Although several studies found that cannabis policy liberalization was associated with decreases in alcohol use measures, these same studies showed no impact of the cannabis policy on cannabis use itself. The lack of a consistent association was robust to subject age, outcome measure (e.g., use, medical utilization, driving), and type of cannabis policy; however, this may be due to the small number of studies for each type of outcome. This paper discusses several notable limitations of the evidence base and offers suggestions for improving consistency and comparability of research going forward, including a stronger classification of cannabis policy, inclusion of measures of the alcohol policy environment, verification of the impact of cannabis policy on cannabis use, and consideration of mediation effects.

Parental influences on marijuana use in emerging adulthood

The purpose of this study was to gain a clearer understanding of the relation between parental relationship qualities and overall emerging adulthood (EA) marijuana use processes. The present study drew from an ethnically and socioeconomially diverse sample of EAs (ages 19-22) and their parents (n = 470) from the Pacific Northwest region. This study used parent-report and child-report data to capture measures of parenting and EA marijuana use outcomes. Latent Class Growth Analysis (LCGA) was used to model trajectories of marijuana use and risk factor analyses were used to examine how marijuana group membership varied by covariates and parental relationship qualities. Results revealed that lower levels of family cohesion and quality of parent-child communication were more likely to predict membership in the high-using groups and moderate-decreasing user groups in comparison to low-to-non users. Results also indicated that lower levels of frequency of parent-child communication were more likely to predict membership in the high-users group compared to the low-to-non users. Regarding parent knowledge of marijuana use, trends toward congruence and underestimation of EA marijuana use predicted membership in the high-using and moderate-decreasing groups compared to the low-to-non users. Study results indicate EAs in their early 20s may be more likely to engage in healthy decision-making regarding marijuana use in an environment that includes warm, supportive parent-child relationships where parents are aware of their EAs use without focusing on their EA's perceptions of risk. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

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.

Cannabis Legalization and Adolescent Use of Electronic Vapor Products, Cannabis, and Cigarettes

OBJECTIVES

Cannabis legalization may have unintended consequences, such as effects on prevalence of adolescent use of other substances. We hypothesize that in states that have legalized recreational cannabis (RCL states), electronic vapor product use ("vaping"), cannabis, and cigarette use among adolescents is more prevalent than in states that have only legalized medical cannabis (MCL states) and states that have neither legalized recreational nor medical cannabis (NL states).

METHODS

Data are from the Center for Disease Control's 2017 Youth Risk Behavior Surveillance Survey (n = 107,665), a nationally representative survey of US high school students. We categorized student responses by cannabis legalization status of the state in which they lived at time of survey, then tested associations between cannabis legalization status and adolescent vaping, cannabis, and cigarette use, using logistic regressions.

RESULTS

Students in RCL states were significantly more likely to report current vaping behaviors compared to NL students [odds ratios (OR's) 2.07-2.21]. Students in cannabis-legal states were significantly more likely to report ever or currently using cannabis compared to NL students (OR's 1.27-1.40). MCL students were significantly less likely to report current cigarette smoking (OR = 0.86) compared to NL students.

CONCLUSIONS

Adolescents in cannabis-legal states were more likely to report vaping and cannabis use compared to adolescents in NL states. Public health officials, policymakers, and clinicians should consider the associations between cannabis legalization and adolescent vaping, cigarette, and cannabis use patterns.

Marijuana liberalization policies and perinatal health

We studied the effect of marijuana liberalization policies on perinatal health with a multiperiod difference-in-differences estimator that exploited variation in effective dates of medical marijuana laws (MML) and recreational marijuana laws (RML). We found that the proportion of maternal hospitalizations with marijuana use disorder increased by 23% (0.3 percentage points) in the first three years after RML implementation, with larger effects in states authorizing commercial sales of marijuana. This growth was accompanied by a 7% (0.4 percentage points) decline in tobacco use disorder hospitalizations, yielding a net zero effect over all substance use disorder hospitalizations. RMLs were not associated with statistically significant changes in newborn health. MMLs had no statistically significant effect on maternal substance use disorder hospitalizations nor on newborn health and fairly small effects could be ruled out. In absolute numbers, our findings implied modest or no adverse effects of marijuana liberalization policies on the array of perinatal outcomes considered.

Youth Cannabis use and Legalization in Canada - Reconsidering the Fears, Myths and Facts Three Years In

Canada legalized and regulated non-medical cannabis in October 2018, and in the lead up to this policy change much debate was generated around the Federal Government's stated objective of "keeping cannabis out of the hands of children and youth". As Canada moved through the process of passing Bill C-45 (the Cannabis Act), a contentious issue was whether the 'public health approach' to legalization with strict regulation guiding Federal policy would protect young people from accessing cannabis and from the potential harms of use. Now that we are several years post-legalization of cannabis, in this brief commentary we reconsider the arguments made about the potential consequences of legalization for youth, centered on three key concerns: that prevalence would significantly increase, that there would be greater incidence of harms to youth brain development, and that there would be increased presentations of severe mental illnesses associated with cannabis use. We also consider how focusing narrowly on clinical outcomes has neglected the association between criminalization and social inequities, where the burdens are disproportionate for marginalized and racialized youth.

Recreational cannabis legalization and alcohol purchasing: a difference-in-differences analysis

Background

Whether recreational cannabis legalization is associated with changes in alcohol consumption (suggesting a potential substitution or complementary relationship) is a key question as cannabis policy evolves, particularly given the adverse health and social effects of alcohol use. Relatively little research has explored this question.

Methods

This study examined the association between recreational cannabis legalization and alcohol purchasing in the USA using an interrupted time series design. We used data from the Nielsen Consumer Panel (2004–2017) from 69,761 households in all 50 states to calculate monthly milliliters of pure ethanol purchased for four beverage categories (beer, wine, spirits, and all alcohol products). We used difference-in-differences models and robust cluster standard errors to compare changes in milliliters of pure ethanol purchased. We fit models for each beverage category, comparing three “policy” states that have legalized recreational cannabis (Colorado, Oregon, and Washington) to states that had not legalized recreational cannabis. In one set of models, a single control state was selected that matched pre-policy purchasing trends in the policy states. In another set, policy states were compared to all states that had not legalized recreational cannabis.

Results

Compared to all other states that did not legalize recreational cannabis, Colorado households showed a 13% average monthly decrease in purchases of all alcoholic products combined (estimate, 0.87; CI, 0.77, 0.98) and a 6% decrease in wine (0.94; CI, 0.89, 0.99). Estimates in Washington were suggestive of an increase in spirits purchased in both the unrestricted (1.24; CI, 1.12, 1.37) and restricted sample (1.18; CI, 1.02, 1.36). Oregon showed a significant decrease in monthly spirits purchased when compared to its selected comparator state (0.87; CI, 0.77, 0.99) and to all other states without legalized recreational cannabis (0.85; CI, 0.77, 0.95).

Conclusions

Results suggest that alcohol and cannabis are not clearly substitutes nor complements to one-another. Future studies should examine additional states as more time passes and more post-legalization data becomes available, use cannabis purchase data and consider additional methods for control selection in quasi-experimental studies.

Dual trajectories of cannabis and alcohol use among young adults in a state with legal nonmedical cannabis

BACKGROUND

Understanding the nature of the association between cannabis and alcohol use within individuals over time in the era of legalized cannabis is of crucial importance for assessing the public health consequences of increasing cannabis use. An important unanswered question is whether cannabis and alcohol use substitute for one another. Specifically, is greater use of one substance associated with less use of the other substance (i.e., a negative association) or are the substances complementary and their association positive?

METHODS

We used 24 consecutive months of data on a young adult sample (n = 774; 56% female, age 18-25 during the study) who drank alcohol in the year prior to enrollment. The sample was recruited in Washington State in 2015/2016 (after legalization of nonmedical cannabis) using media advertisements and community flyers and outreach. Using parallel process latent growth curve models, we assessed three types of association between cannabis and alcohol use across the 24-month period: (1) an association between average levels of cannabis and alcohol use; (2) an association between rates of change in cannabis and alcohol use; and (3) correlations between shorter-term deviations/fluctuations off of longer-term trajectories of level and change in cannabis and alcohol use.

RESULTS

We found a positive association between the average frequency of cannabis and alcohol use; individuals who used cannabis more frequently on average also drank alcohol more frequently on average. Change over time in cannabis use was positively associated with change in alcohol use. There was also a contemporaneous positive association between fluctuations in cannabis and alcohol use.

CONCLUSIONS

Overall, we found no evidence of substitution. Rather, the results suggest a complementary relationship between cannabis and alcohol use, such that the use of cannabis and alcohol rises and falls together.

Recreational Marijuana Legalization and Adolescent Use of Marijuana, Tobacco, and Alcohol

PURPOSE

Given the rapid expansion of recreational marijuana legalization (RML) polices, it is essential to assess whether such policies are associated with shifts in the use of marijuana and other substances, particularly for adolescents, who are uniquely susceptible to negative repercussions of marijuana use. This analysis seeks to provide greater generalizability, specificity, and methodological rigor than limited prior evidence.

METHODS

Youth Risk Behavior Survey data from 47 states from 1999 to 2017 assessed marijuana, alcohol, cigarette, and e-cigarette use among adolescents (14-18+ years; N = 1,077,938). Associations between RML and adolescent past-month substance use were analyzed using quasi-experimental difference-in-differences zero-inflated negative binomial models.

RESULTS

Controlling for other state substance policies, year and state fixed effects, and adolescent demographic characteristics, models found that RML was not associated with a significant shift in the likelihood of marijuana use but predicted a small significant decline in the level of marijuana use among users (incidence rate ratio = .844, 95% confidence interval [.720-.989]) and a small increase in the likelihood of any e-cigarette use (odds ratio of zero use = .647, 95% confidence interval [.515-.812]). Patterns did not vary over adolescent age or sex, with minimal differences across racial/ethnic groups.

CONCLUSIONS

Results suggest minimal short-term effects of RML on adolescent substance use, with small declines in marijuana use and increase in the likelihood of any e-cigarette use. Given the delayed rollout of commercial marijuana sales in RML states and rapid expansion of RML policies, ongoing assessment of the consequences for adolescent substance use and related health and behavioral repercussions is essential.

The effect of cannabis policies on treatment outcomes for cannabis use among U.S. adults

BACKGROUND

Research has explored the impact of various medical cannabis policies on substance use treatment admission in recent years, but we know little about factors related to participants' treatment engagement and outcome. To fill this gap in the existing literature, this study used national data to examine the influence of cannabis policies (decriminalized, medical, and recreational) and referral sources (criminal justice vs. voluntary) on treatment completion and length of stay.

METHODS

Data came from the Treatment Episode Data Set-Discharge (2006-2017) on adults 18+ whose primary drug at treatment admission was cannabis. Difference-in-difference analyses using logistic regression examined the effect of cannabis policies on outpatient treatment completion (yes/no; n = 2,192,807) and length of stay (more/fewer than 90 days; n = 1,863,585) in those with a criminal justice or voluntary referral source.

RESULTS

Cannabis policy was not associated with treatment completion in either those with a criminal justice or voluntary referral source. Compared to individuals in states where cannabis use was strictly illegal, those in states with a decriminalization policy were less likely to stay in treatment for 91+ days regardless of the referral source.

CONCLUSIONS

Cannabis policy appears to have a differential effect on treatment completion versus length of stay, with policy having no impact on successful treatment completion. Specifically, we found that decriminalization policies hinder treatment engagement past 90 days. In this sense, length of stay may be a more useful measure of treatment outcome for research than treatment completion moving forward. Furthermore, our study found that neither medical nor recreational policies affected length of stay or treatment completion, regardless of referral source.

Impact of state-level cannabis legalization on poly use of alcohol and cannabis in the United States, 2004-2017

BACKGROUND

Cannabis policy has shifted toward legalization in many parts of the United States (US). While attention has been focused on whether legalization will lead to changes in cannabis use, it is conceivable that legalization will also affect use of substances that individuals frequently use with cannabis. This study assessed whether cannabis legalization impacted the prevalence of poly use of cannabis and alcohol from 2004 to 2017 and estimated the prevalence of cannabis and alcohol poly use in 2017.

METHODS

Public and restricted-use data from the US 2004-2017 National Survey on Drug Use and Health were analyzed. Data on past-month cannabis and alcohol use were assessed each year. Cannabis legalization was determined by the presence or absence of medical marijuana laws (MML) and recreational marijuana laws (RML) in each state. Difference-in-difference approach was used to estimate the association of MML and RML on cannabis and alcohol use overall and by sociodemographic subgroups (e.g., age, income, education).

RESULTS

Between 2004 and 2017, poly use of cannabis and alcohol increased while alcohol-only use decreased. MML were associated with increases in poly use only among adults over age 50 and among those with higher annual incomes and higher education, while RML were associated with increases in poly use broadly among adults across sociodemographic groups.

CONCLUSIONS

Legalization of cannabis was associated with increases in cannabis-alcohol poly use in the US. RML were associated with increases across demographics, while the impact of MML was more limited to certain sociodemographic groups.

Out-of-state cannabis purchases in the United States

BACKGROUND

Cannabis legalization at the US state level may have implications for cross-border purchases and diversion of legal products. The current study examined the association between out-of-state purchases and 1) cannabis regulations; and 2) the length of time a state has had recreational retail sales.

METHODS

Data come from US respondents who participated in Wave 1 of the International Cannabis Policy Study (ICPS), conducted in August-October 2018. Respondents were aged 16-65 years who had used cannabis in the past 12 months (n = 4320). Respondents were recruited using the Nielsen Consumer Insights Global Panel. Binary logistic regression models examined likelihood of any out-of-state cannabis purchases in the prior year, including differences by cannabis regulations, and time since recreational cannabis retail sales began.

RESULTS

Overall, 15.0 % of US cannabis users had made any out-of-state cannabis purchases in the past 12 months. Respondents in states where recreational cannabis was legal were less likely to make any out-of-state purchases than respondents in states where only medical cannabis was legal (AOR = 0.45, 95 % CI: 0.34-0.60, p < 0.001) and where all cannabis was prohibited (AOR = 0.36, 95 % CI: 0.26-0.50, p < 0.001). Among respondents in 'legal' states, a longer history of legal sales was associated with a lower likelihood of out-of-state cannabis purchases (AOR = 0.82, 95 % CI: 0.72-0.93, p = 0.002).

CONCLUSION

The findings demonstrate that consumers in states where recreational cannabis is legal were less likely to purchase cannabis out-of-state than consumers in states where recreational cannabis is not legal. Future research should examine which states people travel to purchase cannabis and why.