Can smoking cannabis reduce how much people drink? A new laboratory study suggests it can, at least in the short term, but researchers and clinicians urge caution about translating the findings to real-world behavior or endorsing cannabis as a substitute for alcohol.
The Brown University study used a simulated bar—complete with beer on tap, spirits, lighting, and a couch—to approximate a social drinking environment. Researchers recruited 138 mainly non-Hispanic white participants in their mid-20s who were regular consumers of both cannabis and alcohol. Each participant completed three visits during which they smoked cannabis cigarettes of differing potencies in randomized order: high-THC (7.2%), low-THC (3.1%), and a very low-THC placebo (0.03%). After smoking, participants spent two hours in the bar lab with the option to consume up to eight “mini-drinks” (enough to raise blood alcohol concentration to 0.10 g/dL). For each mini-drink they chose not to consume, they earned $3.
Compared with the placebo, the higher-THC joint led participants to consume 27% less alcohol; the lower-THC joint produced a smaller reduction of 19%. Participants also waited longer before taking their first drink after smoking the higher-THC product—about 11 minutes longer (a 48% increase in wait time). Measures of alcohol craving gave mixed results: high-THC cannabis appeared to suppress immediate cravings after smoking, but the lower dose did not, and cannabis did not reliably blunt cue-induced craving (for example, when participants were shown images or their preferred drink).
The study’s findings align with another recent laboratory experiment that reported roughly a 25% reduction in alcohol self-administration after smoking cannabis. Authors and outside experts find the convergence encouraging but stress limits. The Brown team, led by Jane Metrik, PhD, emphasized that their results show short-term reductions in drinking within a controlled setting and do not establish that cannabis substitution is safe or effective in everyday life. Real-world contexts include social pressures, stressors, and environmental cues that may alter behavior. Long-term outcomes, including health effects and the risk of developing cannabis use disorder, remain uncertain.
Public-health implications are especially complex against the backdrop of rising interest in patterns like “California sober,” where people replace or cut back on alcohol using cannabis. Alcohol-related harms are well documented; the CDC estimates about 178,000 U.S. deaths annually tied to excessive alcohol use. But legalized cannabis is newer, and its population-level risks and benefits are less well understood. Some advocates argue cannabis is a comparatively less harmful alternative, while many clinicians warn against viewing cannabis as a harmless substitute.
Clinicians not involved in the study cautioned that these laboratory findings could be misinterpreted as endorsement of substituting one intoxicant for another. “I’d hate to see these findings interpreted as getting intoxicated on cannabis is better than getting intoxicated on alcohol,” said a physician specializing in addiction medicine. Others noted the vagueness of terms like “California sober,” which can mask widely differing patterns of use—from occasional low-THC drinks to frequent smoking of high-potency products—and therefore different risk profiles.
In short, this controlled study suggests that smoking cannabis before drinking can reduce immediate alcohol consumption and delay the first drink under laboratory conditions. However, researchers call for more long-term, real-world research before recommending cannabis substitution as a strategy to reduce alcohol use. They caution that cannabis carries its own risks and that the relationship between alcohol and cannabis varies by individual and context.
