Legal Cannabis Stores Linked to Fewer Opioid Deaths, Study Finds
US counties with higher numbers of legal cannabis dispensaries recorded lower levels of opioid-related deaths relative to other locales, according to a new study from researchers at Yale University and the University of California Davis.
The study, published in the British Medical Journal, found a particularly strong link between the presence of dispensaries and a reduction in deaths associated with synthetic opioids, such as fentanyl.
The researchers are careful to point out that the study does not imply cause and effect. Instead, they say the findings suggest “a potential association between increased prevalence of medical and recreational cannabis dispensaries and reduced opioid related mortality rates.” But more individual-level data is needed, they say, to properly characterize the relationship between cannabis and opioid use.
Cannabis and opioids
While the overall number of opioid-related deaths is starting to decline in the United States, the situation is still considered a serious health epidemic. According to 2018 figures from the Centers for Disease Control and Prevention (CDC), an average of 41 people die each day from prescription opioid overdose, and this accounts for just one-third of the total opioid-related deaths in the United States.
“As the spread of COVID-19 has overtaken global health resources and attention, another health crisis appears to be silently raging in the background: increasing opioid-related overdose deaths,” Greta Hsu, a professor of management at UC Davis and the lead author of the study, said in a statement.
Indeed, according to the University of Michigan’s System for Opioid Surveillance, suspected fatal overdoses appear to have risen again in 2020 during the pandemic; rates are up 15 percent compared to the same time period from 2019.
“But there is an alternative approach to thinking about how to address widespread misuse of opioids: altering the supply of available drugs with potential medical usages in pain management,” Hsu said. “In particular, public health researchers have wondered whether increasing the availability of cannabis, which is generally thought to be a less addictive substance relative to opioids, could be associated with a decrease in opioid-related deaths.”
Trend holds as dispensary numbers rise
The new BMJ study looked at the 812 counties in the United States that had legal cannabis dispensaries as of 2017. Using data on opioid-related mortalities aggregated from the US census and the CDC, and information from Weedmaps on active dispensary operations, the researchers searched for any observable associations between the prevalence of dispensaries and opioid-related deaths.
After controlling for population demographics, the researchers found that counties with a higher number of active dispensaries saw significant reductions in opioid-related mortality rates.
An increase from one dispensary to two per county was associated with an estimated 17 percent reduction in mortality rates associated with opioid use. Going from two to three dispensaries brought about a further reduction of around 8.5 percent.
This association was particularly strong in the case of synthetic opioids (not including methadone), where an increase from one to two dispensaries led to an estimates 21 percent reduction in opioid-related mortality rates.
“As business school researchers, we tracked evolving cannabis markets across the U.S. from 2014 onwards in an effort to understand how this new category of organizations emerged,” Hsu explained.
“We realized, however, that our county-level database could also be used to examine whether the availability of legal cannabis in an increasing number of geographic areas has any implications for opioid misuse. Allowing for legal sale of cannabis is a key step in increasing its availability, since it shifts the cost structure of supplying cannabis, making cannabis more easily and widely accessible to customers.”
Cannabis research relating to opioid use
The new study is the first to examine the relationship between cannabis dispensaries and opioid-related mortality and the more granular county level. But given the observational nature of the study, the researchers also stress that more research is needed to establish any causality and to consider next steps.
The current scientific literature contains mixed results concerning the substitution of cannabis for opioids. Select studies have suggested that daily cannabis use might curb illicit opioid use and that those who inject opioids are less likely to overdose if they are also using cannabis for pain relief. But others have found no evidence that cannabis is actually being substituted for non-medical opioids among current users. One study even observed that the odds of using opioids nearly doubled among its sample population on days where they also used cannabis.
Another study found that “unsupported claims” that cannabis use might help treat opioid use disorders are still being made by some dispensaries, even though there is not yet a clear scientific consensus on the issue.
Writing in an accompanying editorial, the researchers argue that that relaxation of cannabis prohibition “cannot be regarded as a remedy to the opioid crisis until a robust evidence base is available,” but believe that further experimental studies using individual-level data “would inform a more nuanced understanding of the substitution between opioids and cannabis.”