Cannabis May Help Some People Reduce Opioid Use, but Evidence Does Not Yet Show It Treats OUD

A 2024 University of Southern California study suggests that some people who inject drugs use cannabis to manage opioid cravings, withdrawal-related discomfort and anxiety while reducing or stopping opioid use. The findings offer insight into cannabis as a possible harm-reduction tool—but they do not establish that cannabis treats opioid use disorder or works as a substitute for proven medications.

The study, published in Drug and Alcohol Dependence Reports, was funded by the National Institute on Drug Abuse. Researchers conducted 30 semi-structured interviews between July 2021 and April 2022 with people who injected opioids and used cannabis. Participants were recruited at two community sites in Los Angeles, including locations near a syringe-service program and a methadone clinic.

Rather than testing cannabis in a clinical trial, the researchers used qualitative interviews to examine participants’ experiences and perceptions. Across the interviews, participants described three main ways cannabis appeared to support changes in their opioid use:

• Maintaining abstinence or treatment participation: Some participants said cannabis helped them manage anxiety, cravings and other symptoms after they stopped using opioids.
• Managing withdrawal-related discomfort: Participants reported using cannabis for symptoms such as body aches, pain and emotional distress, sometimes reducing how often they injected opioids.
• Providing an easily accessible option: Several participants viewed cannabis as easier to obtain than medications for opioid use disorder, particularly in jurisdictions where cannabis is legal or widely available.

One participant described cannabis as helping prevent the initial urge to use opioids and said it helped them “get over the hump” during the transition away from regular opioid use. Such accounts are important because withdrawal, cravings and treatment access barriers can strongly influence whether people return to opioid use. However, they remain self-reported experiences from a small, geographically limited sample.

The study therefore cannot determine whether cannabis directly reduced opioid consumption. It also did not compare cannabis with a placebo, measure clinical outcomes over time or establish whether cannabis improved treatment retention. Participants may have differed from people who do not use cannabis in ways that influenced their opioid use, and the results may not apply to people with opioid use disorder in other settings.

The authors propose that future harm-reduction programs could examine low-threshold, peer-led cannabis services and the potential use of cannabis alongside medications for opioid use disorder. These are suggestions for further research, not recommendations that cannabis replace established treatment.

According to the Centers for Disease Control and Prevention, the FDA-approved medications for opioid use disorder are buprenorphine, methadone and naltrexone. Medication treatment is associated with lower overdose and mortality risk, while detoxification without medication is not recommended because it can increase the risk of resumed opioid use and overdose.

The USC findings add a community-based perspective to a mixed and still-developing research literature. Earlier observational studies have also reported associations between cannabis use and lower frequency of nonmedical opioid use, but those studies cannot by themselves prove that cannabis caused the reduction. Other research has found no consistent reduction in opioid-withdrawal symptoms from cannabis during methadone tapering.

For now, the strongest conclusion is a limited one: some people who use opioids report that cannabis helps them cope with cravings, withdrawal symptoms and the transition away from opioid use. Whether cannabis can safely and reliably improve outcomes—alone or alongside medications such as buprenorphine or methadone—requires controlled clinical research. The study supports examining patients’ experiences without dismissing them, while keeping evidence-based opioid treatment at the center of care.

People experiencing opioid withdrawal or opioid use disorder should seek medical support rather than attempting withdrawal alone. The Substance Abuse and Mental Health Services Administration provides information on medications and treatment options for opioid use disorder.