Δ9-Tetrahydrocannabinol (THC) impairs visual working memory performance: a randomized crossover trial.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology October 1, 2020 Kirsten C S Adam, Manoj K Doss, Elisa Pabon et al.
THC, the main psychoactive component of cannabis, impairs visual working memory—the ability to temporarily hold information in mind. In two double-blind, randomized crossover experiments, healthy adults performed a visual working memory task after taking oral THC (7.5 or 15 mg) or a placebo. THC reduced working memory performance (effect size d = 0.65), increased self-reported mind wandering, and decreased the accuracy of participants' awareness of their own task performance. The findings suggest that THC disrupts working memory both by increasing mind wandering and by reducing metacognitive monitoring. The study also demonstrated that short task durations and small sample sizes can mask such drug effects.