- In some states in the United States, opioid use disorder is a qualifying condition for the use of medical marijuana.
- However, a new study concludes that there is no evidence that cannabis reduces opioid misuse.
- Experts add that there has never been enough evidence to support the use of cannabis as a treatment option for opioid use disorder.
A new study spanning two decades is reporting there is no evidence to support the claim that cannabis reduces opioid misuse.
The research published in the American Journal of Psychiatry determined cannabis may not be an effective long term strategy for reducing harm to people experiencing opioid use disorder or for people who use opioids problematically.
“There are claims that cannabis may help decrease opioid use or help people with opioid use disorders keep up with treatment. But it’s crucial to note those studies examine short-term impact and focus on treatment of chronic pain and pain management, rather than levels of opioid use in other contexts,” Dr Jack Wilson, the lead author of the study and a postdoctoral research fellow at The Matilda Centre for Research in Mental Health and Substance Use at the University of Sydney in Australia, said in a statement.
“Our investigation shows that cannabis use remains common among this population, but it may not be an effective long-term strategy for reducing opioid use,” he added.
The Australian research is one of the longest studies of its kind and ran from 2001 to 2022.
As part of the study, the researchers enlisted 615 people who had heroin dependence in 2001 and 2002. The subjects were then followed through further interviews at 3, 12, 24 and 36 months. They were also interviewed 11 years and 18 to 20 years later.
Their use of heroin as well as cannabis was assessed at each of these time points.
The researchers found cannabis use was common among people who experience opioid use disorder.
However, they said they found no evidence to suggest cannabis reduced the use of opioids among those in the study.
“When extrapolating these findings, clinicians should give caution to the relationship between cannabis and opioids. These findings provide further evidence that cannabis use remains common among people with long-term opioid use disorder,” the study authors write. “Caution should be taken given the emergence of cannabis-based interventions for individuals using opioids.”
In 2020, it was estimated that
Opioids are drugs that reduce the intensity of feelings of pain and include legal pain medications such as oxycodone, codeine, morphine, and hydrocodone. Illegal drugs include heroin and synthetic opioids often made with substances such as fentanyl.
Opioid use disorder occurs when a person is experiencing a problematic pattern of use of opioids that causes significant distress or impairment.
The person may have been unsuccessful in cutting back or controlling their use of opioids and they may have had problems with work, school, or home life.
In some U.S. states such as New York, policies are in place that consider opioid use disorder a qualifying condition for the use of medical marijuana.
However, Keith Humphreys, PhD, a professor of psychiatry and behavioral sciences and a former senior policy advisor for the White House Office of National Drug Control Policy, says there has never been enough evidence to support such policies.
“There was never really any good evidence that cannabis was a good treatment for opioid use disorder,” Humphreys, who was not involved in the study, told Medical News Today. “That was just a claim that was used very cynically by the industry… and so the fact that it turns out not to be true is not surprising because it was really more of a marketing ploy than it was a serious scientific viewpoint.”
“Parents will come in and say, ‘my son is addicted, but he can’t overdose because he’s smoking cannabis’ and you lose your sense of humor about it really fast when you hear about things like that. Or people are not taking FDA approved medications that can save their lives because they’ve heard that cannabis was somehow protecting themselves. It was just dishonest and it was also kind of cruel,” he added.
Opioid use disorder is a chronic disease, but it is treatable.
Dr. Aimee Moulin is the director of addiction medicine for the University of California Davis Health emergency department. She argues cannabis should not be considered as a treatment option for opioid use disorder.
“For opioid use disorder, we have highly effective treatment in terms of buprenorphine, methadone and to a lesser extent, naltrexone,” Moulin, who was not involved in the study, told Medical News Today. “So we have medications that have been studied and proven to be effective in terms of reducing opioid withdrawal symptoms, as well as decreasing overdose deaths. And so I think that, from my perspective, we should focus on the medications that we know are effective.”
The researchers of the study say there has been a global shift toward legalizing cannabis and recognizing it as a therapeutic product.
However, they argue both policy makers and clinicians should be cautious about relying on cannabis as a strategy to tackle to the opioid crisis.
Dr. Larissa Mooney is a professor of clinical psychiatry and director of the Addiction Psychiatry Division in the Department of Psychiatry and Biobehavioral Sciences at the University of California Los Angeles.
She says misleading claims about the therapeutic use of cannabis may be leading to confusion among the public.
“The laws of the United States really vary in terms of increasing numbers of states are legalizing cannabis for recreational use and other states have medical marijuana laws that really vary in terms of how that medical use is defined,” Mooney, who was not involved in the study, told Medical News Today. “Some states have very liberal medical indications for medical cannabis. But… cannabis is not for this purpose regulated, it’s not a prescription. It’s really just a recommendation letter. There’s just a lot of interest in and many claims that may be misleading about potential therapeutic applications of cannabis. So that messaging may be confusing to some people.”
“When somebody has an opioid use disorder, they should be informed of evidence based treatments, we do have robust approved medications for the treatment of opioid use disorder, and that should remain the mainstay of treatment,” she added.