Heterogeneity of state medical marijuana laws and adolescent recent use of alcohol and marijuana: Analysis of 45 states, 1991–2011

Abstract

Objective: To assess associations between enactment of state medical marijuana laws (MMLs), MML restrictiveness, and past-30-day youth alcohol use overall, and in relation to marijuana use. Method: This quasi-experimental difference-in-difference designed study used state-level Youth Risk Behavior Survey data of 9th–12th grade students in 45 states from 1991–2011 (N D 715,014). We conducted bivariate (unadjusted) and multivariable (adjusted for state, year, individual characteristics) logistic regression analyses to examine the effect of MML enactment (yes/no) and less restrictive vs. more restrictive MMLs on five varying measures of past 30-day alcohol use (i.e., any use or binge) and alcohol and marijuana use behaviors. Results: In the final adjusted analyses, MML enactment was associated with lower odds of adolescent past 30-day (1) alcohol use (OR D 0.92, [0.87, 0.97], p < .01) and (2) use of both alcohol and marijuana (OR D 0.93, [0.87, 0.99], p < .05). States with less restrictive MMLs had lower odds of past 30-day (1) alcohol use (OR D 0.94, [0.92, 0.97], p < .001), (2) binge drinking (OR D 0.96, [0.93, 0.97], p < .05), (3) alcohol use without any marijuana use (OR D 0.96, [0.93, 0.99], p < .01), and (4) use of both alcohol and marijuana (OR D 0.96, [0.92, 0.99], p < .05). Conclusions: This study found that enactment of any MML, and of less restrictive MMLs, was associated with lower odds of past 30-day adolescent alcohol use among adolescents. With continued change in state marijuana laws, it is important to monitor the effect of their enactment and implementation, as well as their specific provisions (e.g. dispensaries, home cultivation), which may differentially affect adolescent behaviors.

ACKNOWLEDGEMENTS

The authors would like to thank The Centers for Disease Control and Prevention for use of the Youth Risk Behavior Survey data and the many State health and education departments for their assistance in providing access to their State's data. The lead author would like to acknowledge: Peter Kreiner, PhD, Rosalie Pacula, PhD, John Knight, MD, Constance Horgan, ScD, and Sharon Reif, PhD for their mentorship at different phases of this study.

FUNDING

This research was primarily supported by the National Institute on Drug Abuse (NIDA) Grants: 5F31DA036923-02 (PI: Julie K. Johnson) and 4T32DA007292-24 (Julie K. Johnson, Abenaa A. Jones, PI: Renee M. Johnson). The primary funder, NIDA, was involved in the review and approval of study design and conduct, but not involved in data collection, management, analysis, data interpretation, or manuscript preparation. Secondary support was provided by NIDA grant K01DA031738-06 (PI: Renee M. Johnson), National Institute on Alcohol Abuse and Alcoholism (NIAAA) grants: T32AA00567 (Julie K. Johnson, Ann Marie Matteucci, PI: Constance Horgan), 1R01AA021904 (Sion K. Harris, PI: John R. Knight), 1R34AA023026 (Sion K. Harris, PI: John R. Knight), 1R01AA02243 (Sion K. Harris, PI: John R. Knight), and the Leadership Education in Adolescent Health Training Program Health Resources and Service Administration Maternal and Child Health (MCH/HRSA) grant T71 MC00009 (Sion K. Harris). The secondary funders were not involved in involved in data collection, management, analysis, data interpretation, or manuscript preparation. This article is the sole responsibility of the authors and does not reflect the view of NIDA, NIAAA, or MCH/HRSA.

AUTHOR CONTRIBUTIONS

Julie Johnson is responsible for the study conception, design, analysis, and manuscript writing. Julie Johnson had full access to all the data in the study takes responsibility for the integrity of the data and the accuracy of the data analysis. All authors assisted with writing and interpretation of findings. Sion Harris, Dominic Hodgkin, and Ann Marie Matteucci also assisted with study conception, design, and analysis.