The results of a popular study that linked medical cannabis programs with lower numbers of opioid overdose deaths were reversed last summer when additional data became available. But statistics say there is a correlation between access to medical cannabis and lower opioid prescriptions. Can cannabis help end the opioid crisis? The answers are hazy.
Much of the hubbub surrounding the subject started in 2014, when a study conducted by researchers at the University of Pennsylvania found that opioid-related deaths were on the decline in states that had medical cannabis programs. Its data ranged from 1999 to 2010. The study's results were gobbled up by marijuana advocates (including your reporter) and repeated ad nauseum.
Last June, a Stanford University School of Medicine team updated the study using the same methods as the first one—but extending the dates through 2017. According to their findings, the 2014 study was completely wrong. With the addition of the new data, they found that states with medical cannabis programs had average rates of opioid overdose deaths that were nearly 23 percent higher than those without programs—the exact opposite of what the earlier data showed.
But the study's authors didn't equate access to medical cannabis with spikes in opioid overdose deaths, however. “We find it unlikely that medical cannabis—used by about 2.5 percent of the US population—has exerted large conflicting effects on opioid overdose mortality,” the authors wrote. “A more plausible interpretation is that this association is spurious … Research into therapeutic potential of cannabis should continue, but the claim that enacting medical cannabis laws will reduce opioid overdose death should be met with skepticism.”
What's especially strange about these findings is that two 2018 studies—one published in JAMA Internal Medicine and the other in Addiction—found that opioid prescriptions for Medicaid enrollees statistically dropped in states where medical cannabis was legal.
Seems like another great endorsement, right?
But another 2018 study from the Journal of Addiction Medicine found that medical cannabis patients were more likely to report using prescription drugs—both medically and nonmedically—than others. And a paper published in 2015 in Drug and Alcohol Dependence claimed that cannabis patients require more pain medications than nonusers. And a study from the American Journal of Psychiatry in 2017 found that marijuana use can increase the chance of developing an opioid use disorder.
Trying to keep up is enough to drive anyone bonkers.
So what can we glean from all this? For one thing: Statistics can be a slippery bunch of weasels if you aren't careful. For another: It's probably best to trust the Stanford team and remain skeptical about any correlations this early in the game. We could easily be trying to force a point here where none exists.
What's important here is to avoid taking stands based solely on their political outcomes and remember that the opioid crisis is an actual threat to our nation's health. If cannabis can't help, it's best to drop the subject and focus on other methods.