Substance Use
Association Between State Cannabis Laws and Opioid Outcomes: A Systematic Review David Fink* David Fink Lauren Gorfinkel Sarah Gutkind Diana Bachowski Zachery Mannes Andrew Saxon Deborah Hasin
AIM: Individuals and communities in the US are increasingly devastated by opioid-related morbidity and mortality. During the same time period these increases occurred, paralleling these increases in opioid-related morbidity and mortality, state medical cannabis laws (MCL) and recreational cannabis laws (RCL) have become increasingly widespread. This study aimed to examine whether cannabis legalization is associated with changes in the prevalence of opioid outcomes.
METHODS: We systematically reviewed the literature in 5 databases (EconLit, EMBASE, MEDLINE, PsycINFO, Web of Science Core Collection) and Google Scholars for titles and articles. We included observational studies published in English that examined the association between state MCL or RCL and opioid-related health outcomes.
RESULTS: Of 1536 articles, 45 met the inclusion criteria. Of these, 17 examined MCL only, 11 examined RCL only, and 8 examined both MCL and RCL. Opioid-related outcomes included opioid prescriptions dispensed (n=14), opioid overdose deaths (n=13), opioid use (n=11), opioid use disorder (n=4), opioid use disorder treatment (n=2), and opioid-related hospital or emergency department visits (n=4). Overall, the current literature is mixed. However, studies using data from 2010 and earlier tended to support an association between MCL and opioid outcomes, but this relationship often became neutral or even negative in more recent years.
CONCLUSIONS: The shift in direction of results from positive to neutral or negative in more recent years may indicate that earlier results involving only MCL were spurious, i.e., the result of unrelated temporal trends in opioid outcomes and cannabis laws, or that the current situation, with cannabis increasingly legalized for recreational purposes, is different from the earlier one. As the number of states legalizing cannabis for recreational use continue to increase, further research on cannabis legalization and opioid outcomes is crucial.