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Researchers debunk claim that medical marijuana is solution to opioid crisis
Legalization of medical cannabis did not reduce the rate of opioid overdose deaths, according to a report recently published in the Proceedings of the National Academy of Sciences.
“Medical cannabis has been touted as a solution to the U.S. opioid overdose crisis since Bachhuber et al found that from 1999 to 2010 states with medical cannabis laws experienced slower increases in opioid analgesic overdose mortality,” Chelsea L. Shover, PhD, of the department of psychiatry and behavioral sciences at Stanford University and colleagues wrote.
“That research received substantial attention in the scientific literature and popular press and served as a talking point for the cannabis industry and its advocates, despite caveats from the authors and others to exercise caution. ... Replicating the Bachhuber et al finding is a worthy task, especially in light of the changing policy landscape,” they added.
Like Bachhuber and colleagues, Shover et al conducted a time-series analysis of medical cannabis laws and state-level death certificate data of all 50 states. They extended the end date to 2017 and had data from 34 more states.
Shover and colleagues found that when analyzing the data from the 1999 to 2010, the time period in the Bachhuber et al study, Shover and colleagues found a “statistically indistinguishable reduction in opioid-related deaths associated with medical cannabis laws.
However, when using data from the full data set from 1999 to 2017, the found that states actually experienced a 22.7% increase (95% CI, 2-47.6) in overdose deaths in states that passed medical cannabis laws.
They also wrote that while data from 2008 to 2012 would have generated results closer to Bachhuber et al, by 2013, that association became ambiguous and by 2017 the data would suggest the opposite of Bachhuber and colleague’s findings. The new study’s authors attributed the differences to greater financial affluence, liberal political mindsets, marijuana-related incarceration rates and more access to naloxone and addiction treatment of the states in the older study.
“We are more cautious than others have been in drawing causal conclusions from ecological correlations and conclude that the observed association between these two phenomena is likely spurious rather than a reflection of medical cannabis saving lives 10 years ago and killing people today,” Shover and colleagues wrote. “Unmeasured variables likely explain both associations.”
Shover also expressed hope that the findings do not dissuade future research into medical cannabis use or opioid-related deaths.
“There are valid reasons to pursue medical cannabis policies, but this doesn't seem to be one of them. I urge researchers and policymakers to focus on other ways to reduce mortality due to opioid overdoses,” she said in a press release. – by Janel Miller
Disclosures: The authors report no relevant financial disclosures.