Science & Health
Opening Legal Marijuana Dispensaries Is Tied To A Huge Drop In Opioid-Related Deaths, Analysis Finds

Counties that have marijuana dispensaries see an average of 30 percent fewer opioid-related deaths compared to counties without legal cannabis shops open, suggesting a substitution effect away from prescription pills and heroin toward the plant-based treatment, according to a new data analysis.
In a Washington Post piece on Wednesday, Harvard University economics student Julien Berman used data from the University of Michigan that identifies dispensary locations at the county level to compare opioid overdose trends over 10 years in jurisdictions where cannabis became legally available compared to those without regulated access.
“The theory is straightforward: making cannabis more available—and reducing its cost—could induce people to shift from opioids, which are super dangerous, to marijuana, a significantly safer alternative,” Berman said. “Existing opioid users seeking pain relief can choose marijuana instead of heroin, especially in counties where recreational use is legal and access is easy. And new potential users might never turn to opioids at all if they could get marijuana instead.”
Other factors were taken into account to support the conclusion, including comparisons of opioid mortality rates in counties within a legal state where some allow retailers to operate and others have chosen to opt out.
“That kind of variation helps rule out other state-level changes such as expanded access to naloxone—a drug that can reverse the effects of an overdose—as the main cause of the drop in deaths,” Berman said.
On average, the opioid death rates following the establishment of cannabis dispensaries declined more sharply in the immediate years after the opening compared to dry counties. But from years five to 10, there’s a more precipitous effect, with an average rate of 27 percent fewer opioid deaths in jurisdictions that have cannabis storefronts after a decade.
There are some limitations to the analysis, including challenges with the “enormous number of messy business records” maintained in the University of Michigan dataset that could have misidentified certain businesses. And it’s possible counties that were assessed could have separately implemented other programs to address opioid use during the timeline that was studied, Berman noted.
“Still, the fact that the drop in deaths shows up right after the first dispensary opens—and not before—strongly suggests that opioid users do shift to marijuana, at least enough to stop overdosing,” he wrote.
He added that while studies have shown that marijuana isn’t entirely harmless, it’s “much safer than heroin.”
“Heck, it’s arguably safer than alcohol. If the dispensary down the street can get people off opioids, public health wins—even if overall marijuana use goes up,” he said.
Relatedly, a recently published study found that, among drug users who experience chronic pain, daily cannabis use was linked to a higher likelihood of quitting the use of opioids—especially among men.
Researchers for a separate federally funded survey recently found an association between state-level marijuana legalization and reduced prescriptions for opioid pain medications among commercially insured adults—indicating a possible substitution effect where patients are choosing to use cannabis instead of prescription drugs to treat pain.
A study published late last year found that legalizing medical cannabis appeared to significantly reduce monetary payments from opioid manufacturers to doctors who specialize in pain, with authors finding “evidence that this decrease is due to medical marijuana becoming available as a substitute” for prescription painkillers.
Other recent research also showed a decline in fatal opioid overdoses in jurisdictions where marijuana was legalized for adults. That study found a “consistent negative relationship” between legalization and fatal overdoses, with more significant effects in states that legalized cannabis earlier in the opioid crisis. Authors estimated that recreational marijuana legalization “is associated with a decrease of approximately 3.5 deaths per 100,000 individuals.”
Another recently published report into prescription opioid use in Utah following the state’s legalization of medical marijuana found that the availability of legal cannabis both reduced opioid use by patients with chronic pain and helped drive down prescription overdose deaths statewide. Overall, results of the study indicated that “cannabis has a substantial role to play in pain management and the reduction of opioid use,” it said.
Yet another study, published in 2023, linked medical marijuana use to lower pain levels and reduced dependence on opioids and other prescription medications. And another, published by the American Medical Association (AMA) last February, found that chronic pain patients who received medical marijuana for longer than a month saw significant reductions in prescribed opioids.
About one in three chronic pain patients reported using cannabis as a treatment option, according to a 2023 AMA-published report. Most of that group said they used cannabis as a substitute for other pain medications, including opioids.
Other research published that year found that letting people buy CBD legally significantly reduced opioid prescription rates, leading to 6.6 percent to 8.1 percent fewer opioid prescriptions.
A 2022 research paper that analyzed Medicaid data on prescription drugs, meanwhile, found that legalizing marijuana for adult use was associated with “significant reductions” in the use of prescription drugs for the treatment of multiple conditions.
A 2023 report linked state-level medical marijuana legalization to reduced opioid payouts to doctors—another datapoint suggesting that patients use cannabis as an alternative to prescription drugs when given legal access.
Researchers in another study, published last year, looked at opioid prescription and mortality rates in Oregon, finding that nearby access to retail marijuana moderately reduced opioid prescriptions, though they observed no corresponding drop in opioid-related deaths.
Other recent research also indicates that cannabis may be an effective substitute for opioids in terms of pain management.
A report published recently in the journal BMJ Open, for instance, compared medical marijuana and opioids for chronic non-cancer pain and found that cannabis “may be similarly effective and result in fewer discontinuations than opioids,” potentially offering comparable relief with a lower likelihood of adverse effects.
Separate research published found that more than half (57 percent) of patients with chronic musculoskeletal pain said cannabis was more effective than other analgesic medications, while 40 percent reported reducing their use of other painkillers since they began using marijuana.
