Substance Use

A Brown University randomized, controlled “bar lab” study of 157 U.S. adults (ages 21–44) who were heavy drinkers and regular cannabis users found that smoking higher‑THC cannabis (7.2%) led participants to drink about 27% less alcohol over the next two hours versus placebo, with a 19% reduction at 3.1% THC. Published in the American Journal of Psychiatry and funded by NIAAA, the trial also showed an immediate drop in the urge to drink, though authors cautioned results may not generalize beyond near‑daily cannabis users, other products, or real‑world settings and do not justify recommending cannabis as a substitute for alcohol.