Overview
- Published in the American Journal of Psychiatry, the Brown University study is the first randomized, placebo-controlled test of cannabis’s causal effect on alcohol consumption.
- The crossover trial enrolled 157 adults who drank heavily and used cannabis at least twice weekly, with participants completing three lab visits for placebo, low THC, and higher THC conditions.
- Participants drank about 19% less after smoking 3.1% THC cannabis and about 27% less after 7.2% THC compared with placebo.
- Active THC doses lowered immediate alcohol craving and delayed the first sip during an Alcohol Choice Task conducted in a bar-like room that offered small cash payments for declining drinks.
- The authors warn the findings are not a recommendation to substitute cannabis for alcohol and report ongoing trials examining concurrent use and different cannabinoids.