One way to reduce opioid overdose death rates in American communities may be to expand legal access to another, less lethal drug. A study published in January 2021 in the BMJ suggests that U.S. counties that have more cannabis dispensaries also have lower opioid-related deaths.
The study focused on 812 counties in 23 U.S. states and the District of Columbia that allowed cannabis dispensaries to sell recreational or medical marijuana. Across all the counties in the study, the average number of cannabis dispensaries increased from slightly less than one per county in 2014 to more than four by 2018.
When the number of cannabis dispensaries in a county increased from one to two, researchers estimated that overall opioid mortality rates fell by 17 percent.
Death rates from synthetic opioids like fentanyl, which are responsible for a greater proportion of opioid fatalities in the United States, dropped by 14 percent when the number of medical marijuana dispensaries increased from one to two, and declined by 21 percent with a similar increase in recreational marijuana dispensaries.
Two things might be driving the reduction in opioid-related deaths in communities with more cannabis dispensaries, says W. David Bradford, PhD, a professor of public policy and administration at the University of Georgia in Athens who wasn’t involved in the study.
“First, the availability of cannabis in the local community leads to substitution away from opioids, and that substitution slows the advancement of opioid use disorder in some people, which reduces risky opioid use and so reduces accidental death,” Dr. Bradford says.
It’s also possible that there are some situations where cannabis dispensaries open up in communities that tend to lure lots of other new businesses as well — typically places with lower crime rates and higher household incomes, Bradford says. Some of these safer, more affluent neighborhoods that are attractive locations for new dispensaries may already have lower opioid death rates than places where dispensaries don’t open, he says.
Most likely, both substitution of opioids for less lethal cannabis and community characteristics share responsibility for the connection between rising numbers of dispensaries and falling opioid death rates, Bradford says.
Mixed Results From Previous Studies
A pivotal study published in JAMA Internal Medicine offered an early, promising look at the potential for legalized marijuana to contribute to a reduction in opioid overdose deaths. This study found that states that legalized medical marijuana from 1999 to 2010 had significant reductions in opioid overdose mortality rates; rates fell by about 19 percent in the first year after legalization and by more than 33 percent by the sixth year.
More recently, a study published in June 2019 in the Proceedings of the National Academy of Sciences used the same methods to revisit the connection between legalization of medical marijuana and opioid deaths. For the period from 1999 to 2010, this newer study found results similar to the older study. But when the new study looked at data covering a longer period of time, from 1999 to 2017, and more states, researchers found medical cannabis laws associated with an almost 23 percent increase in opioid overdose deaths.
What the current study offers is a more granular look at what happens not just at the state level, but within local communities where differences in how drug policies are implemented can have a profound impact. That’s because state laws legalizing cannabis don’t necessarily mean all communities in the state offer similar access to marijuana, the study authors write in the BMJ.
Linking county-level information on the number of dispensaries and county-level opioid death rates offers a more complete picture of how expanded access to marijuana might influence fatalities related to opioids, says one of the coauthors, Balázs Kovács, PhD, an associate professor in management at Yale University in New Haven, Connecticut.
“Our main argument is that legal cannabis dispensaries provide access to substitutes for opioids,” Dr. Kovács says.
More Research Is Needed
Studies that focus on what happens with drug use and overdose deaths at the individual level when cannabis dispensaries open are necessary, Kovács notes. In particular, he says, this might help answer one major question raised in the current study: Why do cannabis dispensaries appear to have the biggest impact on overdose deaths related to synthetic opioids like fentanyl?
Data on individual drug users matters because not all people will have the same experience when there are broad shifts in public policy, such as state laws legalizing marijuana, says Chelsea Shover, PhD, an assistant professor in residence at the David Geffen School of Medicine at the University of California in Los Angeles.
One person given access to legal marijuana, for example, might turn to cannabis as a way to manage chronic pain instead of misusing opioids, Dr. Shover says. But many other people might not do this.
Within neighborhoods and communities, there may be varying levels of access to drug treatment programs and initiatives to help prevent overdose deaths among people with addiction, Shover adds. The same communities where dispensaries open may also have more robust services to prevent or treat opioid use disorder, Shover says.
Not many studies have looked at data on local cannabis dispensaries, and more research is needed to better understand how these businesses impact drug use and health outcomes for people who use drugs, Bradford notes.
“So far everyone is doing ecological studies: what happens to people or doctors when their local conditions change,” Bradford says. “None of us have been able to connect actual medical cannabis use with actual medical outcomes for individual people.”