Review of 63 neuroimaging studies finds adolescent cannabis users show brain changes, but causation remains unclear
A review of 43 studies on adolescent cannabis users and 20 on age-of-onset effects found compromised frontoparietal structure and function, but whether these changes are caused by adolescent-specific use or general cannabis factors remains uncertain.
Quick Facts
What This Study Found
Adolescent cannabis users showed alterations mainly in frontal and parietal regions and associated brain activation related to inhibitory control, reward, and memory. However, adult studies examining onset age were more mixed, with many not finding age-of-onset effects on brain imaging metrics.
Key Numbers
43 studies on adolescent cannabis users; 20 studies on onset age effects in adults. Most consistent findings in frontal and parietal regions related to inhibitory control, reward, and memory.
How They Did This
PubMed and Scopus searches for empirical neuroimaging studies examining brain effects in adolescent cannabis users and adult studies exploring age-of-onset effects. 43 adolescent user studies and 20 onset-age studies identified.
Why This Research Matters
Determining whether adolescence is a uniquely vulnerable period for cannabis effects on the brain, or whether observed differences reflect general use factors, has major implications for policy and prevention.
The Bigger Picture
The disconnect between adolescent user studies (showing consistent effects) and adult onset-age studies (showing mixed results) suggests confounders like depressive symptoms or use chronicity may be driving some findings.
What This Study Doesn't Tell Us
Most underlying studies are cross-sectional; difficulty separating adolescent-specific effects from general cannabis use factors; varied definitions of "adolescent" across studies; limited control for confounders.
Questions This Raises
- ?Are the brain changes observed in adolescent cannabis users driven by the developmental timing of use or by correlated factors like mental health symptoms?
Trust & Context
- Key Stat:
- 43 adolescent user studies vs. 20 onset-age studies gave divergent results
- Evidence Grade:
- Comprehensive review of neuroimaging literature, but most underlying studies are cross-sectional with limited control for confounders.
- Study Age:
- Published in 2020.
- Original Title:
- Cannabis Use in Adolescence: A Review of Neuroimaging Findings.
- Published In:
- Journal of dual diagnosis, 16(1), 83-105 (2020)
- Authors:
- Chye, Yann(5), Christensen, Erynn(2), Yücel, Murat(11)
- Database ID:
- RTHC-02469
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Is the adolescent brain more vulnerable to cannabis?
Studies directly comparing adolescent users to non-users consistently show brain differences. However, studies in adults that examined whether earlier onset of use matters gave mixed results, suggesting it is still unclear whether adolescence is uniquely vulnerable or whether other factors explain the findings.
What brain areas are most affected?
Frontal and parietal regions were most consistently implicated, particularly in relation to inhibitory control, reward processing, and memory. Adolescent cannabis users often showed hyperactive brain responses to task-based stimuli compared to non-users.
Read More on RethinkTHC
Cite This Study
https://rethinkthc.com/research/RTHC-02469APA
Chye, Yann; Christensen, Erynn; Yücel, Murat. (2020). Cannabis Use in Adolescence: A Review of Neuroimaging Findings.. Journal of dual diagnosis, 16(1), 83-105. https://doi.org/10.1080/15504263.2019.1636171
MLA
Chye, Yann, et al. "Cannabis Use in Adolescence: A Review of Neuroimaging Findings.." Journal of dual diagnosis, 2020. https://doi.org/10.1080/15504263.2019.1636171
RethinkTHC
RethinkTHC Research Database. "Cannabis Use in Adolescence: A Review of Neuroimaging Findin..." RTHC-02469. Retrieved from https://rethinkthc.com/research/chye-2020-cannabis-use-in-adolescence
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.