Recreational cannabis laws and opioid-related emergency department visit rates.

The opioid epidemic in the United States has accelerated during the COVID-19 pandemic. As of 2021, roughly a third of Americans now live in a state with a recreational cannabis law (RCL). Recent evidence indicates RCLs could be a harm reduction tool to address the opioid epidemic. Individuals may use cannabis to manage pain, as well as to relieve opioid withdrawal symptoms, though it does not directly treat opioid use disorder. It is thus unclear whether RCLs are an effective policy tool to reduce adverse opioid-related health outcomes. In this study, we examine the impact of RCLs on a key opioid-related adverse health outcome: opioid-related emergency department (ED) visit rates. We estimate event study models using nearly comprehensive ED data from 29 states from 2011 to 2017. We find that RCLs reduce opioid-related ED visit rates by roughly 7.6% for two quarters after implementation. These effects are driven by men and adults aged 25-44. These effects dissipate after 6 months. Our estimates indicate RCLs did not increase opioid-related ED visits. We conclude that, while cannabis liberalization may offer some help in curbing the opioid epidemic, it is likely not a panacea.