Study: Marijuana use appears to increase rather than decrease risk of opioid use disorder

Marijuana use may be associated with an increased risk of developing a prescription opioid use disorder, according to new research published in the American Journal of Psychiatry.

“The idea that marijuana could help curb the opioid epidemic, which has received a fair amount of media attention based on population trends, struck me as clinically counterintuitive. I wanted to see if it held up when you follow a large number of adults who do and do not smoke marijuana,” said study author Mark Olfson, a professor of clinical psychiatry at Columbia University.

An epidemic of opioid overdoses is taking place in the United States. The drugs, such as OxyContin, Percocet and Vicodin, are prescribed for moderate to severe pain.

Previous research found that states that have legalized medical marijuana also have fewer opioid-related deaths. But the new findings raise some doubts about the role of marijuana.

The researchers analyzed data from the National Epidemiologic Survey on Alcohol and Related Conditions, a nationally representative survey of 43,093 U.S. adults conducted in 2001-2002. The survey conducted follow-up interviews with 34,653 of the original participants three years later.

Olfson and his colleagues found evidence that marijuana use was linked to an increased risk of developing an opioid use disorder. Those who reported using marijuana at the beginning of the survey were more likely to have opioid use disorder three years later. Those who used marijuana more often were more likely to develop an opioid use disorder.

“People who smoke marijuana are at increased rather than decreased risk of developing problems with opioids including clinical opioid use disorders,” Olfson told PsyPost. “However, most people who smoke marijuana do not develop opioid use disorders.”

It is unclear why marijuana use would increase the risk of abusing opioids. One possibility is that people with access to marijuana are more likely to have access to other drugs of abuse.

“An important caveat is that we were unable to examine the effects of medical marijuana,” Olfson noted. “It is possible that in carefully selected individuals, for example people who have chronic pain and nonmedical opioid use, marijuana tends to decrease rather than increase dependence on opioids.”

The research was supported by a grant from the National Institute on Drug Abuse.

“There remains so much we don’t understand about what is driving the recent increase in opioid-related morbidity and mortality,” Olfson said. “Following people at high risk represents an important means for gaining insight into the drivers of the opioid epidemic and developing more effective strategies for interrupting progression from opioid use to addiction.”

The study, “Cannabis Use and Risk of Prescription Opioid Use Disorder in the United States“, was also co-authored by Melanie M. Wall, Shang-Min Liu and Carlos Blanco.