Cannabis-related psychotic-like experiences in teens were partly explained by changes in a specific brain region
In 706 adolescents scanned at ages 14 and 19, cannabis use was linked to psychotic-like experiences, and this relationship was partially mediated by reduced growth of the uncus, a specific region of the parahippocampal gyrus.
Quick Facts
What This Study Found
Psychotic-like experiences were associated with reduced expansion of the right uncus between ages 14 and 19 (p=0.002). A mediation analysis showed a significant total effect of cannabis use on psychotic-like experiences (b=0.069, p<0.001), with a small but significant indirect effect through uncus development (0.004, 95% CI 0.0004-0.01, p=0.026).
Key Numbers
706 adolescents scanned at 14 and 19. Significant association between PLEs and reduced right uncus expansion (p=0.002 cluster, p=0.018 peak). Total cannabis-to-PLE effect: b=0.069, p<0.001. Indirect effect through uncus: 0.004, p=0.026.
How They Did This
Longitudinal neuroimaging study of 706 adolescents from the IMAGEN consortium with structural MRI at ages 14 and 19. Deformation-based morphometry mapped brain changes. Cannabis use assessed with ESPAD, psychotic-like experiences with CAPE questionnaire. A priori mediation model tested.
Why This Research Matters
This study identifies a specific brain structural change that partly explains how cannabis use during adolescence may contribute to psychotic-like experiences, providing a biological mechanism for a well-documented epidemiological association.
The Bigger Picture
Finding a brain structural mediator between cannabis use and psychotic symptoms in the general population strengthens the biological plausibility of the cannabis-psychosis link and identifies a potential biomarker for vulnerability.
What This Study Doesn't Tell Us
The mediation effect through the uncus was small, suggesting other pathways are also important. Observational study cannot establish causation. Cannabis use was self-reported. Only two imaging time points. Sample was from the general population with subclinical symptoms, not patients with psychotic disorders.
Questions This Raises
- ?Could uncus development be used to identify adolescents at risk for cannabis-related psychosis?
- ?What other brain regions contribute to the remaining cannabis-psychosis pathway?
- ?Would cannabis cessation allow normal uncus development to resume?
Trust & Context
- Key Stat:
- Uncus development partially mediated cannabis-psychosis link (p=0.026)
- Evidence Grade:
- Longitudinal neuroimaging study with appropriate mediation analysis, but small indirect effect and observational design.
- Study Age:
- 2020 study from the IMAGEN consortium. One of few studies identifying specific brain structural mediators of cannabis-related psychotic experiences.
- Original Title:
- Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus.
- Published In:
- Journal of the American Academy of Child and Adolescent Psychiatry, 59(5), 642-649 (2020)
- Authors:
- Yu, Tao, Jia, Tianye, Zhu, Liping, Desrivières, Sylvane, Macare, Christine, Bi, Yan, Bokde, Arun L W, Quinlan, Erin Burke, Heinz, Andreas, Ittermann, Bernd, Liu, ChuanXin, Ji, Lei, Banaschewski, Tobias, Ren, Decheng, Du, Li, Hou, Binyin, Flor, Herta, Frouin, Vincent, Garavan, Hugh, Gowland, Penny, Martinot, Jean-Luc, Paillère Martinot, Marie-Laure, Nees, Frauke, Orfanos, Dimitri Papadopoulos, Luo, Qiang, Chu, Congying, Paus, Tomas, Poustka, Luise, Hohmann, Sarah, Millenet, Sabina, Smolka, Michael N, Vetter, Nora C, Mennigen, Eva, Lei, Cai, Walter, Henrik, Fröhner, Juliane H, Whelan, Robert, He, Guang, He, Lin, Schumann, Gunter, Robert, Gabriel
- Database ID:
- RTHC-02929
Evidence Hierarchy
Follows a group of people over time to track how outcomes develop.
What do these levels mean? →Frequently Asked Questions
What is the uncus?
The uncus is a hook-shaped structure in the parahippocampal gyrus, part of the brain's medial temporal lobe. It is involved in memory and emotion processing and is relevant to both normal brain development and psychosis.
Does this prove cannabis causes psychosis?
This study found a brain structural pathway that partially explains the statistical link between cannabis use and psychotic-like experiences, but the observational design cannot confirm causation. The mediation effect was small, suggesting multiple factors are involved.
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Cite This Study
https://rethinkthc.com/research/RTHC-02929APA
Yu, Tao; Jia, Tianye; Zhu, Liping; Desrivières, Sylvane; Macare, Christine; Bi, Yan; Bokde, Arun L W; Quinlan, Erin Burke; Heinz, Andreas; Ittermann, Bernd; Liu, ChuanXin; Ji, Lei; Banaschewski, Tobias; Ren, Decheng; Du, Li; Hou, Binyin; Flor, Herta; Frouin, Vincent; Garavan, Hugh; Gowland, Penny; Martinot, Jean-Luc; Paillère Martinot, Marie-Laure; Nees, Frauke; Orfanos, Dimitri Papadopoulos; Luo, Qiang; Chu, Congying; Paus, Tomas; Poustka, Luise; Hohmann, Sarah; Millenet, Sabina; Smolka, Michael N; Vetter, Nora C; Mennigen, Eva; Lei, Cai; Walter, Henrik; Fröhner, Juliane H; Whelan, Robert; He, Guang; He, Lin; Schumann, Gunter; Robert, Gabriel. (2020). Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus.. Journal of the American Academy of Child and Adolescent Psychiatry, 59(5), 642-649. https://doi.org/10.1016/j.jaac.2019.05.034
MLA
Yu, Tao, et al. "Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus.." Journal of the American Academy of Child and Adolescent Psychiatry, 2020. https://doi.org/10.1016/j.jaac.2019.05.034
RethinkTHC
RethinkTHC Research Database. "Cannabis-Associated Psychotic-like Experiences Are Mediated ..." RTHC-02929. Retrieved from https://rethinkthc.com/research/yu-2020-cannabisassociated-psychoticlike-experiences-are
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.