The Impact of Recreational Cannabis Legalization on Cannabis Use in U.S. Adults From 2016 to 2023: A Quasi-Experimental Study.

Abstract

Although cannabis use has increased during a time of expanding cannabis legalization, there is limited evidence on how use has shifted in response to legalization across at-risk groups. This study examined the impact of recreational cannabis legalization on adult cannabis use overall and by demographic and higher-risk strata. Behavioral Risk Factor Surveillance System 2016-2023 surveys (N=859,600 adults from 38 states) were linked to state recreational cannabis legalization. Using quasi-experimental difference-in-differences zero-inflated negative binomial and probit regressions, the impact of legalization on cannabis use was examined overall and by demographic (age, sex, education, race/ethnicity) and higher-risk (mental health, cigarette smoking, alcohol use) strata, adjusting for demographic and policy controls, state, and year. Data were compiled in 2024-2025 and analyzed in 2025. Recreational cannabis legalization was associated with 44% lower odds of zero cannabis use (95% CI=40%, 48%), indicating higher likelihood of any use, not with a greater frequency of use among users, and a significant total effect estimate, indicating higher cannabis use after legalization. When cannabis use was dichotomized, legalization was associated with a 0.94 percentage point increase in the likelihood of use (95% CI=0.04, 1.84), a 9.8% relative increase compared with 2016 levels. Adults aged ≥60 years, female, White, or college educated had generally lower cannabis use, yet significant interactions (all p<0.1) revealed that they were the most responsive to legalization, with 1-2 percentage point increases in use. Recreational cannabis legalization is driving increases in cannabis use among groups with historically lower use rather than increasing use among those who already used cannabis.