Cannabis Policy and Consumption: Taking into account Substitution Effects

Background: Previous studies examining the cannabis-alcohol substitution effect have found that medical cannabis policies may result in substituting the use of cannabis in place of alcohol use. Objectives: This study adds to the literature on cannabis-alcohol substitution by analyzing the effect of decriminalization, medicinal cannabis, and adult-use legalization cannabis policies (2002-2019) on cannabis and alcohol use and substance substitution for all 50 states and the District of Columbia (N=867). Results: Results support the notion that liberalized cannabis policies can increase the prevalence of cannabis use. An adult-use legalization specific analysis yielded findings suggesting a complex and heterogenous effect of such laws on cannabis-alcohol complementation. Conclusion: Given the lack of clarity and heterogenous effects of cannabis laws, policy makers should carefully take into consideration the benefits of medical cannabis laws, along with the risks of decriminalization and adult-use legalization.