Acute effects of partial CB1 receptor agonists on cognition – A meta-analysis of human studies

In Summary:
Cannabis is one of the most widely consumed psychoactive plants in the world, and THC is the main component responsible for cannabis’ psychological effects - namely the sense of relaxation and euphoria. However, cognitive impairment is a side effect frequently observed in those who consume cannabis.
To gain a thorough understanding of the acute effects of administration of cannabis, THC and similar compounds such as dronabinol (the synthetic form of THC), nabilone (a synthetic analog of THC) on cognition in adults, clinical researchers at the Faculty of Medicine, University of Montreal, Canada recently performed a meta-analysis. The meta-analysis synthesized findings from 52 experimental studies that assessed cognitive dysfunction in 1580 non-psychiatric, healthy adult volunteers following administration of the above compounds. They found that cannabis, THC and its synthetic forms impaired all aspects of cognition, including verbal learning, verbal memory, working memory, speed of processing, attention, executive function, and impulsivity. Among these, the largest negative impact was on verbal learning, verbal memory, and working memory. Further sub-analyses on age and gender indicated that while the mean age of participants had no impact on the results, a greater ratio of males to females in a study was associated with greater cannabinoid-induced deficits in speed of processing and impulsivity found by that study.
Through this inclusive, large-scale meta-analysis, the authors attempted to present the scientific community, medical community, and consumers alike with a thorough, impartial understanding of how consumption of cannabis and cannabis-derived psychoactive compounds may immediately affect cognition in healthy adults. This is a realm previously less understood than the effects of cannabis in chronic users.

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