• Justin Matheson, Robert E Mann, Beth Sproule, Marilyn A Huestis, Christine M Wickens, Gina Stoduto, Tony P George, Jürgen Rehm, Bernard Le Foll, and Bruna Brands.
• Department of Pharmacology and Toxicology, Faculty of Medicine, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S3H7, Canada; Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, 33 Russell Street, Toronto, Ontario M5S2S1, Canada. Electronic address: justin.matheson@camh.ca.
• Pharmacol. Biochem. Behav. 2020 Jul 1; 194: 172937.

ObjectivesTo examine acute and residual mood and cognitive performance in young adult regular cannabis users following smoked cannabis.MethodsNinety-one healthy young adults completed this double-blind, placebo-controlled, parallel-groups study. Participants were randomized to receive active (12.5% THC) or placebo cannabis with a 2:1 allocation ratio, and mood [Profile of Mood States (POMS)] and cognitive performance [Hopkins Verbal Learning Test - Revised (HVLT-R), Digit Symbol Substitution Test (DSST), Continuous Performance Test (CPT), grooved pegboard (GPB)] were assessed before and 1, 24, and 48 (h) after smoking cannabis ad libitum. High and Low THC groups were based on blood THC concentrations.ResultsOne hour after smoking cannabis, compared to Placebo, in both the High and Low THC groups, there were increases in POMS Arousal and Positive Mood, and in the High THC group only, increases in Confusion, Friendliness, and Elation, and a decrease in Fatigue. Increases in Friendliness and Elation in the High THC group remained significant for 24 h. The only significant acute effect of cannabis on cognition was a decrease in the percent of words retained in the HVLT-R in the High THC group compared to Placebo (mean difference = 15.8%, 95% CI = 3.6-28.0%, p = 0.006). Unexpectedly, compared to Placebo, both the High and Low THC groups improved in DSST performance at 48 h (p ≤ 0.016).ConclusionsUnder the present experimental conditions, in young regular cannabis users, smoking cannabis ad libitum had significant effects on mood, some of which persisted 24 h later, yet minimal effects on cognition, and no evidence of residual cognitive impairment.Copyright © 2020 Elsevier Inc. All rights reserved.

31 keywords...

hide…