In a randomized placebo-controlled crossover trial, 125 adults who drank heavily and used cannabis at least twice weekly smoked placebo, 3.1% THC, or 7.2% THC cannabis cigarettes. Participants with higher working memory capacity, measured by a symmetry span task, reported significantly lower alcohol urge after smoking the higher THC dose compared to placebo. Lower working memory, measured by an n-back task, was linked to higher alcohol urge overall but did not alter cannabis's effect on urge. The authors suggest that individuals with lower working memory may be less likely to experience reduced alcohol craving from cannabis.
Smoking cannabis acutely reduces alcohol consumption in people who drink heavily and use cannabis at least twice weekly. In a double-blind crossover trial, 157 participants were randomized to smoke cannabis cigarettes with 7.2% THC, 3.1% THC, or placebo (0.03% THC) across three days. After smoking, they were exposed to alcohol cues and given a choice to consume alcohol. Those who smoked 3.1% THC reduced alcohol consumption by 19%, and those who smoked 7.2% THC reduced it by 27%, compared to placebo. No significant effects on overall craving were found, though the higher dose reduced alcohol urge immediately after smoking. Further research on various cannabinoids is needed to inform alcohol treatment guidelines.