The first obstacle is that the medical community has largely resolved the question of whether cannabis is clinically useful. In January, the National Academies of Sciences, Engineering and Medicine (NAS) reported that there is “conclusive evidence” that cannabis (both whole plant and extracts) is clinically effective at treating some diseases, including chronic pain. Cannabis may prove to be a pain management strategy that could substitute for opioids for many desperate patients, and the National Institute on Drug Abuse (NIDA) acknowledges that cannabis may be an effective tool to combat the opioid crisis. Researchers studying the relationship between medical cannabis laws and opioid use have found that states with such laws have nearly a 25 percent reduction in opioid-related deaths. The contrast between opioids — which killed more than 33,000 Americans in 2015 — and cannabis could not be more striking. As NIDA states on its DrugFacts — Marijuana Web page: “There are no reports of teens or adults fatally overdosing (dying) on marijuana alone.”

Further, medical cannabis may also save lives in unexpected ways. Data published in the American Journal of Public Health in February suggests that laws allowing it were associated with fewer traffic fatalities. While we always have to be careful about making claims that a policy caused an outcome, evidence from multiple studies, with careful statistical analyses, is building a case that medical cannabis has real, beneficial, spillover effects.