Associations between state-level policy liberalism, cannabis use, and cannabis use disorder from 2004 to 2012: Looking beyond medical cannabis law status (2019)

Background: Medical cannabis laws (MCL) have received increased attention as potential drivers of cannabis use (CU), but little work has explored how the broader policy climate, independent of MCL, may impact CU outcomes. We explored the association between state-level policy liberalism and past-year cannabis use (CU) and cannabis use disorder (CUD).
Methods: We obtained state-level prevalence of past-year CU and CUD among past year cannabis users for ages 12-17, 18-25, and 26+ from the 2004-2006 and 2010-2012 National Surveys on Drug Use and Health. States were categorized as liberal, moderate, or conservative based on state-level policy liberalism rankings in 2005 and 2011. Linear models with random state effects examined the association between policy liberalism and past-year CU and CUD, adjusting for state-level social and economic covariates and medical cannabis laws.
Results: In adjusted models, liberal states had higher average past-year CU than conservative states for ages 12-17 (+1.58 percentage points; p = 0.03) and 18-25 (+2.96 percentage points; p = 0.01) but not for 26+ (p = 0.19). CUD prevalence among past year users was significantly lower in liberal compared to conservative states for ages 12-17 (-2.87 percentage points; p = 0.045) and marginally lower for ages 26+ (-2.45 percentage points; p = 0.05).
Conclusion: Liberal states had higher past-year CU, but lower CUD prevalence among users, compared to conservative states. Researchers and policy makers should consider how the broader policy environment, independent of MCL, may contribute to CU outcomes.