A systematic review of 90 neuroimaging studies found preliminary evidence that adolescent cannabis use is associated with structural and functional alterations in multiple brain networks.
Parents, educators, neuroscience researchers, policymakers
90 studies, 9,441 participants reviewed
What the researchers found
Across 90 studies including 9,441 participants (3,924 cannabis users, 5,517 non-users), preliminary evidence pointed to alterations in frontoparietal, frontolimbic, frontostriatal, and cerebellar regions among adolescent and emerging adult cannabis users.
Why it matters
With cannabis legalization expanding and adolescent perceptions of harm declining, establishing what happens to the developing brain during cannabis exposure is critical for public health messaging and clinical guidance.
The numbers in context
90 studies; 9,441 total participants; 3,924 cannabis users; 5,517 non-users; alterations in 4 major brain networks
How the study worked
Systematic search of Medline and PsycInfo with additional non-systematic sources, identifying 90 structural and functional neuroimaging studies of cannabis use during adolescence and emerging adulthood.
What this study cannot tell us
Divergent results across studies make definitive conclusions difficult. Most studies are cross-sectional, so risk factors for cannabis use and consequences of use are difficult to disentangle.
How to read the evidence
Comprehensive systematic review of 90 studies, though individual study quality varies and most are cross-sectional.
When this study was published
Published in 2022
The bigger picture
This is the most comprehensive neuroimaging review of adolescent cannabis effects to date. While findings point toward brain changes, the authors emphasize that larger, more rigorous studies are needed to separate risk factors from consequences.
Questions still open
- Are the observed brain changes reversible with abstinence? Do cannabis potency and frequency of use moderate brain effects? Are there critical windows during adolescence when the brain is most vulnerable?
Common questions
What brain regions are affected by adolescent cannabis use?
Does cannabis permanently change the adolescent brain?
Read the original research
Systematic review of structural and functional neuroimaging studies of cannabis use in adolescence and emerging adulthood: evidence from 90 studies and 9441 participants.
Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 47(5), 1000-1028
Citation
Lichenstein, Sarah D; Manco, Nick; Cope, Lora M; Egbo, Leslie; Garrison, Kathleen A; Hardee, Jillian; Hillmer, Ansel T; Reeder, Kristen; Stern, Elisa F; Worhunsky, Patrick; Yip, Sarah W. (2022). Systematic review of structural and functional neuroimaging studies of cannabis use in adolescence and emerging adulthood: evidence from 90 studies and 9441 participants.. Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology, 47(5), 1000-1028. https://doi.org/10.1038/s41386-021-01226-9
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