Medical marijuana laws and their effect on opioid related mortality

The U.S. is currently in the midst of an opioid epidemic. In 2015, an estimated 12.5 million people misused opioid prescriptions. In 2016 alone, approximately 62,000 Americans died from an opioid overdose. The enactment of medical marijuana laws may help stem the rise in these deaths if medical marijuana can be used as a substitute for more powerful opioid pain relievers. Currently, 29 states have some form of a medical marijuana law in place, with California being the first in 1996 and West Virginia being the most recent in 2017. In this study, we use state level data from the Centers for Disease Control to test the hypothesis that medical marijuana can act as a prescribed substitute for opioid pain relievers and have the potential benefit of reducing deaths related to opioids in states with these laws. We use a difference-in-difference framework that takes advantage of variation in the timing of the enactment of these laws across states to identify whether they affect opioid-related death rates. Unlike previous work, we find little evidence that the enactment of MMLs has reduced opioid death rates. However, we do find that the presence of a legal dispensary may reduce opioid deaths. This information is useful for policymakers who are increasingly looking for policies to reduce opioid deaths.