ABSTRACT
To determine if marijuana legalization reduced opioid mortality, the U.S. opioid and fentanyl subset death trends during the 2010-2019 decade were compared in states and District of Columbia (D.C.) (jurisdictions) that had implemented marijuana legalization with states that had not. Acceleration of opioid mortality during 2020, first year of the COVID-19 pandemic, was also compared in recreational and medicinal-only legalizing jurisdictions. Joinpoint methodology was applied to Centers for Disease Control and Prevention WONDER data. Trends in legalizing jurisdictions were cumulative aggregates. The overall opioid and fentanyl death rates and percentage of opioid deaths due to fentanyl increased more during 2010-2019 in jurisdictions that legalized marijuana than in those that did not (pairwise comparison p=0.007, 0.05, and 0.006, respectively). By 2019, the opioid and fentanyl death rates were 44% and 50% greater in the legalizing than non-legalizing jurisdictions, respectively. When the COVID-19 pandemic hit in 2020, jurisdictions that implemented recreational marijuana legalization before 2019 had significantly greater increases in both overall opioid and fentanyl death rates than jurisdictions with medicinal-only legalization. For all opioids, the mean (95% confidence interval [CI]) 2019-to-2020 increases were 46.5% (95% CI, 36.6% to 56.3%) and 29.1% (95% CI 20.2% to 37.9%), respectively (p=0.02). For fentanyl, they were 115.6% (95% CI, 80.2% to 151.6%) and 55.4% (95% CI, 31.6% to 79.2%), respectively (p=0.01). Marijuana legalization is correlated with worsening of the U.S. opioid epidemic, and especially during the COVID-19 pandemic with recreational legalization.