Evidence on the acute and residual neurocognitive effects of cannabis use in adolescents and adults: a systematic meta-review of meta-analyses.
Level 1 - systematic review of randomized trials
Systematic meta-review of meta-analyses
PubMed 35048456 · doi:10.1111/add.15764
What was done
A systematic meta-review searched PubMed, PsycINFO, Web of Science, and Google Scholar for meta-analyses quantitatively examining the cognitive task performance of cannabis users from the general population. Ten meta-analyses representing 71 effect sizes and 43,761 participants were synthesized across six cognitive domains: executive functions (k = 7), learning and memory (k = 5), attention (k = 4), processing speed (k = 5), perceptual motor function (k = 2), and language (k = 2).
What was found
Included meta-analyses provided evidence ranging from low to moderate quality. Verbal learning and memory had the most robust evidence and greatest acute impairment, which persisted after intoxication passed. Executive functioning showed small-to-moderate acute and residual adverse effects, specifically small deficits in inhibitory processes and cognitive flexibility, and small-to-moderate deficits in working memory and decision-making. Processing speed and attention showed small-to-moderate acute adverse effects, with residual neurocognitive deficits observed in heavy-using youths. Simple motor skills had small-to-moderate effects, and language showed no significant difference between users and non-users. Exact numerical effect sizes, point estimates, and confidence intervals were not reported in the abstract.
Why it matters
This overview consolidates evidence that cannabis-related neurocognitive deficits are not limited to acute intoxication but persist into the post-intoxication period, particularly for verbal memory and executive function.
Limits
The primary meta-analytic evidence was rated only low-to-moderate in quality. The abstract does not provide numerical effect sizes, definitions of residual abstinence timeframes, or breakdowns by cannabis potency, product type, or administration route.
Cited by
- supports Regular cannabis use impairs short-term memory, concentration, and the ability to keep track of details.