Cannabis May Help Heavy Drinkers Cut Back on Alcohol, New Federally Funded Study Finds

Marijuana use is associated with reduced alcohol intake and diminished cravings among heavy drinkers, according to a new federally funded study that offers evidence cannabis may serve as a harm reduction tool.

The research, conducted by scientists at Colorado State University, the University of Colorado Boulder, and the University of Colorado Anschutz Medical Campus, is described as the first study to directly test the effects of legal-market cannabis on alcohol use. It was supported by the National Institutes of Health’s National Institute on Alcohol Abuse and Alcoholism and published in Drug and Alcohol Dependence.

Cannabis Before Alcohol Reduced Intake by 25 Percent

Researchers recruited 61 heavy drinkers who also used cannabis several times a week. Each participant took part in two sessions, both conducted in a mobile laboratory set up outside their homes to avoid federal restrictions on handling cannabis in university facilities.

In one session, participants drank alcohol only. In the other, they first consumed cannabis they had legally purchased, followed by alcohol. In both conditions, participants received a standard “priming” drink and were then offered up to four additional drinks.

On average, participants drank about 25 percent fewer alcoholic beverages after consuming cannabis compared to alcohol-only sessions. Many also reported reduced cravings when cannabis was involved.

“Findings from this novel human laboratory study provide initial support for the idea that legal-market cannabis can serve as substitute for alcohol among some individuals who engage in heavy drinking,” the authors concluded.

Substituters vs. Non-Substituters

The study broke participants into groups:

• Substituters (23 participants): Drank significantly less after cannabis use and consistently reported lower cravings.

• Non-substituters (23 participants): Consumed the same amount or more alcohol, showing little change in cravings.

• Abstainers (15 participants): Declined to drink in both sessions regardless of cannabis use.

The results suggest cannabis does not universally reduce drinking, but for a significant subset of heavy drinkers, it may act as an effective substitute.

Limitations and Future Directions

The authors cautioned about limitations. Cannabis was always consumed before alcohol, so it’s unclear if results would differ in the reverse order. The mobile lab, while innovative, may not fully replicate social drinking environments. The sample was also not broadly representative, with participants primarily white and male.

Still, the researchers emphasized the importance of further exploring cannabis as a potential harm reduction tool, particularly for individuals struggling with alcohol misuse but not seeking total abstinence.

Broader Context of Cannabis and Alcohol Research

The study adds to growing evidence that cannabis may reduce problematic drinking:

• Earlier this year, a University of Sydney study funded by the Australian National Health and Medical Research Council found cannabidiol (CBD) could reduce voluntary alcohol consumption in animal models.

• Another federally funded paper published in Nature concluded CBD helps treat alcohol use disorder by easing withdrawal symptoms, lowering relapse risk, and providing neuroprotective effects.

• Polling indicates cultural shifts are already underway: one in three millennials and Gen Z workers reported choosing THC-infused beverages over alcohol for social activities such as after-work happy hours.

Harm Reduction Implications

Alcohol misuse remains one of the leading causes of preventable death globally, and effective treatment options are limited. The possibility that cannabis, already the most widely used substance among people who drink could help reduce alcohol consumption provides a new avenue for harm reduction research and policy.

“Those who drank less after cannabis reported greater decreases in alcohol craving,” the study authors wrote, suggesting substitution effects could become a valuable part of future recovery approaches.

With federal funding backing this line of research, cannabis is increasingly being studied not only as a medical treatment in its own right but also as a tool to address broader public health challenges. 

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