- New research found that U.S. counties with more legal cannabis dispensaries had lower rates of opioid-related deaths.
- Opioids are a class of drugs that include heroin, synthetic opioids such as fentanyl, and prescription pain relievers such as oxycodone, codeine, and morphine.
- However, because of the way the study was designed, the researchers can’t show that the dispensaries were directly responsible for the lower opioid-related deaths.
U.S. counties with legal cannabis dispensaries had lower numbers of opioid-related deaths between 2014 and 2018, including deaths due to synthetic opioids, finds a
During the last year of this study, 46,802 people died of an opioid overdose in the United States. Two-thirds of these deaths were due to synthetic opioids such as fentanyl, according to the
More recent data suggests that the COVID-19 pandemic has worsened the opioid crisis in the United States, with synthetic opioid deaths increasing more than 38 percent from June 2019 to May 2020, reports the CDC.
However, experts caution that the new study suffers from the same limitations as other ecological, or population-level, cannabis studies, and the data used for the analysis is already several years old.
In the study, researchers looked at data from 812 U.S. counties within 23 states that allowed legal cannabis dispensaries by the end of 2017. Researchers combined this with data on opioid-related deaths in those counties.
Opioids are a class of drugs that include heroin, synthetic opioids such as fentanyl, and prescription pain relievers such as oxycodone, codeine, and morphine.
Prescription opioids are used to relieve short-term (acute) and sometimes long-term (chronic) pain.
However, there’s less evidence that they work for chronic pain. These drugs can lead to opioid misuse or addiction, especially with longer use.
In the study, researchers found that counties with more legal cannabis dispensaries had lower rates of opioid-related deaths.
Their analysis showed that increasing the number of dispensaries in a county from one to two was linked to a 17 percent drop in deaths due to opioids.
This was true for both medical and recreational dispensaries, wrote the authors of the study.
The association was even stronger for synthetic opioids other than methadone. Increasing from one to two dispensaries in a county was linked to a 21 percent decline in deaths due to synthetic opioids.
The researchers took into account factors that could have affected opioid use, such as unemployment rates, average income levels, and the number of men in a county.
However, because of the way the study was designed, the researchers can’t show that the dispensaries were directly responsible for the lower opioid-related deaths.
Chelsea Shover, PhD, an assistant professor in the division of general internal medicine and health services research at UCLA School of Medicine, said one of the strengths of the study is that the researchers examined the data at the more fine-grained county level.
However, she said the study still shares the same limitations as other ecological cannabis studies.
“[The study] can’t tell us at an individual level whether people who use cannabis are using fewer opioids, not starting opioids, or not dying from opioids,” she said.
In addition, Shover pointed out that the researchers didn’t take into account how prevalent opioids — in particular, synthetic opioids — were in each county.
“A lot of the counties that are contributing to this particular study are on the West Coast,” she said, in states that had lower levels of synthetic opioids in 2018.
And with researchers only looking at data for a limited time window, it’s hard to know what the situation would look like today.
“If you were to do the same study with current data, you’d find something different because of the way both opioid deaths and cannabis dispensaries have shifted since then,” Shover said.
This isn’t to say that making cannabis more easy to access legally — especially by people with chronic pain — won’t reduce opioid-related deaths.
“You can imagine that if someone uses cannabis for pain relief instead of prescription opioids, they won’t have the opportunity to become dependent on opioids and then potentially transition to heroin or synthetic opioids,” Shover said.
But this study, she said, can’t tell you whether that’s true.
Dr. Chinazo O. Cunningham, a professor at Albert Einstein College of Medicine, agrees that there are limits to these kinds of population-based studies.
“There is potentially a role for cannabis to reduce opioid use,” she said. “However, research [in this area] is mixed, and the studies are mostly ecological. So, it’s difficult to know at the individual patient level exactly what’s happening.”
One possible, and important, role for cannabis is providing people with chronic pain an alternative to opioids.
Because of the high misuse potential of opioids, many healthcare providers are less likely to prescribe them.
“As a physician, what I see more and more is that people have terrible chronic pain, and they have more and more difficulty finding opioids to treat their pain,” Cunningham said.
Knowing how well cannabis works for chronic pain — and for which types of pain — means doing more rigorous studies at the individual patient level.
Right now, though, these studies are difficult for researchers to carry out.
Although many states have approved cannabis for medical or recreational use, the federal government still classifies this drug as a Schedule I substance.
That means there are restrictions on what kind of cannabis research can be done.
Cunningham has two research projects looking at the use of cannabis by people with chronic pain. Both studies are being done at the individual patient level.
“It’s taken me over a year to even get a study approved because of all of the legal issues and concerns about cannabis being a Schedule I substance,” she said.
Shover is also concerned that ecological studies may distract from other work that could help reduce opioid-related deaths among those with opioid use disorders.
“The time we spend talking about how opening cannabis dispensaries might prevent fentanyl overdoses is time that we’re not expanding [the use of] naloxone, reforming criminal justice reentry, improving access to housing, and providing support services that go along with that,” she said.