The belief that expanding cannabis access plays a role in mitigating opioid use and abuse came under fire this week after a newly published paper in the journal PLoS ONE failed to replicate observational findings initially documenting this trend.
Both studies employed similar methodology. Investigators evaluated whether the passage of medical cannabis legislation was associated with later changes in opioid-related mortality. The first study, published in the “Journal of the American Medical Association” in 2014, reported that opioid overdose deaths fell significantly in the years following marijuana liberalization. By contrast, the most recent paper reports that this effect reversed over time. Authors also failed to identify a similar decline in opioid-related mortality in states that have more recently enacted medical marijuana-related laws.
Why the disparate results? One factor likely has to do with the differing inclusion criteria utilized in