United States Marijuana Legalization and Opioid Mortality Trends Before and During the First Year of the COVID-19 Pandemic

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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This study did not receive any funding ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: N/A I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors. The data sources used are available online at CDC WONDER via .