New Study: Heavy Drinkers Cut Alcohol Intake by Almost 30% After Using Cannabis
Key Takeaways
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Cannabis may reduce short-term alcohol intake — heavy drinkers consumed up to 27% less alcohol after smoking higher-THC cannabis.
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Immediate urge to drink decreased, but deeper, long-term alcohol cravings were not consistently reduced.
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The study used THC-only, smoked cannabis, meaning results may not apply to edibles, vapes, or other cannabinoids like CBD.
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Participants were near-daily cannabis users, so occasional users may experience different outcomes.
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Researchers stress that cannabis should NOT be used as a treatment for alcohol-use disorder; long-term effects remain unclear.
A new study suggests that for certain people, using cannabis may significantly reduce how much alcohol they consume.
Researchers at Brown University’s Center for Alcohol and Addiction Studies investigated whether cannabis impacts alcohol cravings and actual drinking behavior — particularly in heavy drinkers who also use marijuana regularly. Their findings indicate that smoking cannabis, especially products with higher THC levels, may reduce alcohol intake in the short term.
Study Overview
The randomized, controlled trial included 157 adults aged 21–44 who all reported:
- Heavy alcohol use
- Regular cannabis consumption (at least twice per week)
Each participant completed three two-hour laboratory sessions. In each session, they smoked a different type of cannabis:
- High-THC (7.2%)
- Low-THC (3.1%)
- Placebo (no THC)
After smoking, participants entered a simulated “bar lab,” where they could choose to drink alcohol or take cash instead.
Key Findings
Higher THC = Lower Alcohol Intake
The group that smoked the 7.2% THC cannabis drank about 27% less alcohol compared to the placebo group. They also reported a sharp, immediate drop in the urge to drink.
Those who smoked 3.1% THC cannabis reduced alcohol consumption by about 19%.
“After people smoked cannabis, they drank about a quarter less alcohol over the next two hours,”
said lead author Jane Metrik, Ph.D., a professor at Brown.
Craving Effects Were Mixed
While cannabis reduced the immediate urge to drink, researchers noted that it didn’t consistently reduce deeper alcohol cravings. Metrik explained that cannabis likely affects alcohol motivation through multiple mechanisms.
The study was funded by the National Institute on Alcohol Abuse and Alcoholism and published in the American Journal of Psychiatry.
Limitations of the Research
The study comes with several important caveats:
1. Only THC Was Tested
Researchers examined smoked cannabis containing THC only. Today’s cannabis market includes vapes, edibles, beverages, and cannabinoids like CBD, CBN, CBG, etc. Results may not apply across these product types.
2. Participants Were Near-Daily Cannabis Users
People who use cannabis infrequently might respond differently.
3. No Study of Mixing Alcohol + Cannabis
The research did not evaluate what happens when people consume both substances together — a common real-world scenario.
4. Lab Environment, Short Time Frame
Since this was a controlled, short-term experiment, it’s unclear whether reduced drinking would last in normal daily life.
5. Not a Treatment Recommendation
Researchers emphasized that the study does not support using cannabis as a substitute for alcohol for people with alcohol-use disorder.
“We do not have clear evidence of long-term safety or efficacy,” Metrik said. “I would not recommend using cannabis to cut down on alcohol use.”
She encouraged anyone already substituting cannabis for alcohol to monitor their consumption carefully and consider evidence-based alcohol treatments.
Expert Reactions
Alcohol Declines as Cannabis Rises
Marcel Bonn-Miller, Ph.D., a cannabis researcher at Ajna BioSciences, said the findings reflect broader market data: alcohol sales often drop in regions where THC products become more accessible.
He noted that many consumers now choose THC beverages as alcohol alternatives and encouraged future research into how non-smoked cannabis products influence drinking patterns over time.
A Rare, High-Quality Cannabis Study
Riana Durrett, director of the Cannabis Policy Institute at UNLV, praised the study’s tightly controlled design.
“It’s logistically difficult to give cannabis in a lab because of federal restrictions, so this is a unique and rigorous experiment,” she said.
Durrett added that the results align with the growing “California sober” trend — reducing alcohol or other drugs while continuing to use cannabis.
What This Means
This study adds to a growing body of research suggesting that cannabis may act as a short-term substitute for alcohol in some people. But researchers stress that it’s far too early to recommend cannabis as a harm-reduction tool without more long-term data.
For now, the takeaway is simple:
Cannabis may temporarily reduce alcohol consumption for heavy drinkers — but it’s not a proven treatment, and both substances carry their own risks.
How does cannabis influence your alcohol consumption? Please let us know in the comments. If you want to take a closer look at the original study we quote, you can check it out here.
