Associations Between State Cannabis and Alcohol Policy Restrictiveness and College Students’ Cannabis Use, Binge Drinking and Co-Use

College students' substance use was sensitive to state cannabis policies after accounting for state alcohol policies. In states with less restrictive cannabis policies, cannabis use and co-use were more common, suggesting complementarity. Within non-legal states, more restrictive alcohol policies were linked to higher cannabis use odds, suggesting substitution. State CPS and APS scores may inform policymakers' efforts to reduce college students' substance use. Future studies should replicate findings in contemporary cohorts, explore social justice implications, and consider concurrent campus and community policies.