Simon Zhornitsky1, Julie Pelletier2, Roxane Assaf3, Sarah Giroux4, Chiang-Shan R Li5, Stephane Potvin6. 1. Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, United States of America. 2. Department of Psychiatry, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada. 3. Department of Psychiatry, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada; Centre de recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montreal, QC, Canada. 4. Department of Psychology, Université de Montréal, Montréal, QC, Canada. 5. Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06519, United States of America; Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, United States of America; Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06520, United States of America. 6. Department of Psychiatry, Faculty of Medicine, Université de Montréal, Montréal, QC, Canada; Centre de recherche de l'Institut Universitaire en Santé Mentale de Montréal, Montreal, QC, Canada. Electronic address: stephane.potvin@umontreal.ca.
Abstract
BACKGROUND: Impairment in cognition is frequently associated with acute cannabis consumption. However, some questions remain unanswered as to which deficits are most prominent and which demographic groups are most vulnerable. METHODS: A literature search yielded 52 experimental studies of acute administration of partial CB1 receptor agonists (i.e. cannabis, THC, and nabilone) that assessed cognitive dysfunction in 1580 healthy volunteers. Effect size estimates were calculated using the Comprehensive Meta-Analysis for the following six cognitive domains: attention, executive functions, impulsivity, speed of processing, verbal learning/memory, and working memory. RESULTS: There were small-to-moderate impairments across all cognitive domains. Deficits in verbal learning/memory and working memory were more prominent, whereas attention and impulsivity were the least affected. Meta-regression analysis revealed that the greater the male ratio is in a sample, the greater the negative effect of cannabinoids on speed of processing and impulsivity. Analysis of route of administration showed that the deficits in speed of processing were smaller in the oral, relative to smoking, vaping, and intravenous administration studies. A publication bias was observed. DISCUSSION: Verbal learning/memory and working memory are most prominently affected by acute administration of partial CB1 receptor agonists. The results are consistent with the residual cognitive effects that have been documented among chronic cannabis users.
BACKGROUND: Impairment in cognition is frequently associated with acute cannabis consumption. However, some questions remain unanswered as to which deficits are most prominent and which demographic groups are most vulnerable. METHODS: A literature search yielded 52 experimental studies of acute administration of partial CB1 receptor agonists (i.e. cannabis, THC, and nabilone) that assessed cognitive dysfunction in 1580 healthy volunteers. Effect size estimates were calculated using the Comprehensive Meta-Analysis for the following six cognitive domains: attention, executive functions, impulsivity, speed of processing, verbal learning/memory, and working memory. RESULTS: There were small-to-moderate impairments across all cognitive domains. Deficits in verbal learning/memory and working memory were more prominent, whereas attention and impulsivity were the least affected. Meta-regression analysis revealed that the greater the male ratio is in a sample, the greater the negative effect of cannabinoids on speed of processing and impulsivity. Analysis of route of administration showed that the deficits in speed of processing were smaller in the oral, relative to smoking, vaping, and intravenous administration studies. A publication bias was observed. DISCUSSION: Verbal learning/memory and working memory are most prominently affected by acute administration of partial CB1 receptor agonists. The results are consistent with the residual cognitive effects that have been documented among chronic cannabis users.