Cannabis has no clear effect on treatment of opioid addiction, US study finds

Cannabis is not an effective treatment for opioid addiction, a new peer-reviewed study of thousands of people being treated for opioid use disorder suggests.

Experts, publishing their results today in The American Journal of Drug and Alcohol Abuse, have found that cannabis is having no significant effect on peoples’ use of opioids, taken outside of medical guidance.

The findings have substantial implications for U.S treatment programmes, some of which still require patients to abstain from cannabis before they qualify for potentially life-saving treatment. This is based on the belief they are more likely to use opioids non-medically if they are using cannabis.

The opposing, and increasingly popular, viewpoint, that cannabis can help wean people with opioid use disorder off opioids, is also called into question in this new study.

Around 120 people die a day from drug overdoses involving opioids (prescription, such as oxycodone, and non-prescription, such as heroin) and opioid use disorder and related deaths cost the US economy more than $1 trillion a year.

As cannabis gains popularity among individuals with opioid use disorder in the U.S., its medicinal use is now legally recognized in thirty-seven states and Washington D.C. While pain remains the most common reason for medical cannabis authorization (i.e., “medical cannabis registration card”), an increasing number of states are adding “alternatives to opioids” or “opioid-treatable disorders” to their lists of approved conditions. In certain states, this includes treatment for opioid use disorder.

It isn’t clear, however, whether cannabis helps or hinders the treatment of opioid use disorder. Some studies have found it helps alleviate pain and opioid withdrawal, but others suggest it makes a return to opioids more likely.

“Clarifying how cannabis and opioids interact is crucial if we are to equip healthcare professionals to provide evidence-based addiction treatment, prevent overdose deaths and save lives,” says researcher Gabriel Costa, of University of Ribeirão Preto in Brazil.

Reference: Cannabis has no clear effect on treatment of opioid addiction, US study finds; The American Journal of Drug and Alcohol Abuse; DOI: 10.1080/00952990.2023.2287406