Certain people who use cannabis tend to drink less alcohol, a new study found.
Researchers from Brown University’s Center for Alcohol and Addiction Studies set out to determine whether cannabis use has an effect on alcohol craving and consumption — specifically, whether smoking marijuana can reduce alcohol use in heavy drinkers.
The randomized, controlled study included 157 adults between the ages of 21 and 44 who reported heavy drinking and regular cannabis use (at least bi-weekly).
Each participant completed three two-hour “lab sessions” with different types of cannabis use. They received one of two levels of THC or a placebo, and then were given the choice to drink alcohol or accept a cash payment.
Those who smoked cannabis with the higher level of THC (7.2%) consumed about 27% less alcohol than those who smoked a placebo. They also reported an immediate reduction in the urge to drink.
Participants who smoked cannabis with 3.1% THC smoked about 19% less alcohol.
“In our controlled bar lab study, after people smoked cannabis, they drank about a quarter less alcohol over the next two hours,” lead study author Jane Metrik, Ph.D., professor of behavioral and social sciences at Brown’s Center for Alcohol and Addiction Studies, told Fox News Digital.
Cannabis had mixed effects on alcohol cravings, the researchers reported.
“We found a significant decrease in alcohol urge immediately after smoking cannabis, but not a consistent effect on a different measure of alcohol craving,” Metrik said. “This suggests that cannabis may not exert a uniform effect on alcohol motivation, and that other mechanisms may also explain how cannabis impacts subsequent alcohol use.”
The study, which was funded by the National Institute on Alcohol Abuse and Alcoholism, was published last month in the American Journal of Psychiatry.
Risks and limitations
The study did have limitations, the researchers acknowledged.
“The study tested only one cannabinoid (THC) in smoked cannabis, which means the results may not generalize to the wide range of cannabis products, formulations and other cannabinoids,” Metrik told Fox News Digital. “The study sample also consisted of individuals who used cannabis nearly every day, so those who use cannabis less often may show different alcohol-related behaviors.”
The researchers also did not look at the effects of using cannabis and alcohol at the same time.
As the research was short-term and conducted in a “lab” setting, it’s unclear whether the reduced alcohol use would continue in the longer term or in real-world settings, they noted.
The study results do not justify recommending cannabis as a substitute for alcohol among people with alcohol-use disorder, the researchers stated, as the long-term health effects and addiction risks for cannabis remain uncertain.
“It is important to understand that cannabis’ impact varies substantially across individuals,” Mitek said, noting that while the substance may reduce drinking in the short term, it also presents its own risks.
“Our study is a first step, and we need more long-term research before drawing conclusions for public health,” she said. “We do not have clear evidence of long-term safety and efficacy of using cannabis as alcohol treatment. For now, I would not recommend using cannabis to cut down on alcohol use.”
For people who are already substituting cannabis for alcohol, Mitek recommends that they closely monitor their use and be aware of the risk of cannabis use disorder. She also “strongly encourages” them to consider evidence-based alcohol treatments.
Experts weigh in
Marcel Bonn-Miller, Ph.D., a cannabis researcher with Ajna BioSciences in Colorado, noted that the study highlights the current market trends, which show that alcohol sales have decreased significantly as THC has become more accessible.
“As many consumers report using THC beverages and other non-inhaled methods of administration as alternatives to alcohol, it would be important for future clinical trials to determine the effect of these formats on alcohol use behavior over time,” the researcher, who was not involved in the study, told Fox News Digital.
Riana Durrett, director of the Cannabis Policy Institute at the University of Nevada, Las Vegas, praised the study’s “rigorous” design.
“Overall, the experimental design is a rare feature in this area of research because it can be logistically difficult to give people cannabis in the lab (given its federal Schedule I status), so this is a really unique study,” Durrett, who was also not involved in the study, told Fox News Digital.
The results align with the “California sober” trend, where smoking cannabis may be a way to reduce other substance use, she noted.
While some individuals have reported that cannabis has helped them recover from other substance use disorders, the effect hasn’t been tested extensively, according to Durrett.
The expert agreed that while the study infers cannabis use does decrease alcohol use in a single session, there are some unknowns, including the long-term effects of cannabis use on alcohol consumption.
“So, it is still possible that in the longer term, cannabis use may be harmful for drinking outcomes,” she said. “We also don’t know the net effect of swapping out one substance (such as alcohol) for another (such as cannabis).”
“It might be easy to believe that using cannabis instead of alcohol is a win, but we really don’t know if that is true or not from the current research.”
Durrett added, “Hopefully, this study and similar ones can add tools to our toolkit on how to reduce problem drinking.”
Mitek noted that additional research is needed to evaluate “clinically relevant alcohol outcomes,” particularly among people who are seeking treatment for alcohol-use disorder.
