By the final year included in the Stanford analysis, 47 states had approved medical marijuana. As they nearly ran out of states that had no such laws, researchers looked at deaths in each state before and after passage, asking what happened over time.
There have been other studies of the issue and there are lots of conflicting claims about marijuana and opioid deaths. But Shover said the “big takeaway for me here is if policymakers are pursuing cannabis legalization as a way to address the opioid crisis, it’s probably going to be disappointing.”
More effective measures, she said, are well-known: wider availability of treatment for addiction and increased distribution of naloxone, the antidote to opioid overdoses, among others.