Marijuana legalization and opioid deaths
研究发现，医用大麻合法化，尤其是通过零售药房销售时，与阿片类药物死亡率上升相关；娱乐用大麻合法化也可能增加死亡率，机制可能与非法芬太尼的出现有关。
Many states have legalized marijuana over the last two decades, initially for medical purposes and more recently for recreational consumption. Despite prior research, it remains unclear how these policies are related to rates of opioid-involved overdose deaths, which have trended rapidly upwards over time. We examine this question in two ways. First, we replicate and extend previous investigations to show that the prior empirical results are frequently fragile to the choice of specifications and time periods, and probably provide an overly optimistic assessment of the effects of marijuana legalization on opioid deaths. Second, we present new estimates suggesting that legal medical marijuana, particularly when available through retail dispensaries, is associated with higher opioid mortality. The results for recreational marijuana, while less reliable, also indicate that retail sales may be correlated with greater death rates relative to the counterfactual of no legal cannabis. A likely mechanism for these effects is the emergence of illicit fentanyl, which has increased the riskiness of even small positive effects of cannabis legalization on the consumption of opioids.