A new study from Brown University suggests that cannabis use may lead to a short-term reduction in alcohol consumption among heavy drinkers, though researchers caution that the findings are preliminary and do not justify recommending marijuana as a substitute for alcohol.
According to Fox News, researchers at Brown’s Center for Alcohol and Addiction Studies conducted a randomized, controlled trial to examine whether smoking cannabis affects alcohol craving and intake.
The study involved 157 adults, ages 21 to 44, who reported heavy drinking and regular cannabis use at least twice per week.
Participants attended three two-hour lab sessions in which they smoked cannabis containing either a high level of THC (7.2%), a lower level (3.1%), or a placebo.
Following each session, they were offered the choice to drink alcohol or accept a cash reward.
Those who used the higher THC cannabis consumed roughly 27% less alcohol than those who received the placebo.
Participants using the lower THC cannabis drank about 19% less. Many also reported an immediate reduction in the urge to drink.
“In our controlled bar lab study, after people smoked cannabis, they drank about a quarter less alcohol over the next two hours,” said lead author Jane Metrik, Ph.D., professor of behavioral and social sciences at Brown.
Metrik noted that while the study found a significant decrease in alcohol urge immediately after cannabis use, the effect was not consistent across all measures of alcohol craving.
“This suggests that cannabis may not exert a uniform effect on alcohol motivation,” she said.
The researchers acknowledged several limitations, including the focus on only one cannabinoid (THC), the short-term lab setting, and the study’s heavy cannabis users.
They also did not examine the simultaneous use of cannabis and alcohol or long-term outcomes.
“It is important to understand that cannabis’ impact varies substantially across individuals,” Metrik said. She stressed that the study does not provide evidence that cannabis is a safe or effective treatment for alcohol-use disorder.
External experts praised the study’s design. Riana Durrett, director of the Cannabis Policy Institute at UNLV, called it “rigorous” and noted that it aligns with trends like the “California sober” movement, where some people use cannabis in place of alcohol.
While cannabis may reduce drinking in single sessions, both Metrik and Durrett emphasized the need for more research on long-term outcomes and the risks of substituting one substance for another. “We really don’t know if that is true or not from the current research,” Durrett said.
The study was funded by the National Institute on Alcohol Abuse and Alcoholism and published last month in the American Journal of Psychiatry.
