Research & Resources

Researchers conducted a narrative review of studies published between January 1, 2015, and December 31, 2020, to assess the effects of cannabis policies on the use of alcohol in the United States and Canada. 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 alcohol policy environment measures, verification of the impact of cannabis policy on cannabis use, and consideration of mediation effects.

This paper, “Relationships of cannabis policy liberalization with alcohol use and co-use with cannabis: A narrative review,” was funded by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) and published in the journal Alcohol Research: Current Reviews.