Chronic Cannabis Users Show Brain Activation Changes in Social Thinking That Resemble Psychosis Risk Patterns
Brain imaging found that chronic cannabis users showed altered activation patterns in regions involved in understanding other people's mental states, similar to patterns seen in people at risk for psychosis.
Quick Facts
What This Study Found
Fifteen chronic cannabis users and 14 controls underwent brain imaging while performing a theory of mind task (interpreting cartoon stories that required understanding characters' intentions). Cannabis users showed less activation in the left parahippocampal gyrus, right precuneus, and right cuneus, but greater activation in the left cuneus and right anterior cingulate gyrus.
These activation patterns resembled those previously documented in populations at risk for developing psychosis, suggesting that cannabis use affects social cognitive processing in ways that parallel other psychosis risk factors.
Key Numbers
15 cannabis users vs. 14 controls. Altered activation found in 5 brain regions: reduced in left parahippocampal gyrus, right precuneus, right cuneus; increased in left cuneus and right anterior cingulate gyrus.
How They Did This
Functional brain imaging (fMRI) during performance of a cartoon story task requiring theory of mind. Fifteen chronic cannabis users were compared to 14 healthy controls. Brain activation patterns were analyzed for between-group differences.
Why This Research Matters
Theory of mind, the ability to understand what others are thinking and feeling, is a core social cognitive skill that is impaired in schizophrenia. Finding that chronic cannabis users show similar brain activation abnormalities suggests cannabis may affect the neural circuits underlying social cognition.
The Bigger Picture
This study adds to the evidence linking chronic cannabis use to psychosis-like brain changes. The social cognition angle is particularly relevant because theory of mind deficits are among the most functionally disabling aspects of psychotic disorders, affecting relationships and daily functioning.
What This Study Doesn't Tell Us
The sample was small (15 users, 14 controls), limiting statistical power. The cross-sectional design cannot determine whether cannabis use caused the brain changes or whether pre-existing differences led people to use cannabis. Other substances used by participants could have contributed to the findings.
Questions This Raises
- ?Do these brain activation changes reverse with cannabis abstinence?
- ?Do they predict who will go on to develop psychotic disorders?
- ?Are the activation changes associated with actual impairments in real-world social functioning?
Trust & Context
- Key Stat:
- Activation patterns matched those seen in psychosis at-risk populations
- Evidence Grade:
- Small cross-sectional neuroimaging study; preliminary evidence that cannot establish causation.
- Study Age:
- Published in 2012. Neuroimaging research on cannabis and social cognition has expanded with larger samples.
- Original Title:
- Alterations of theory of mind network activation in chronic cannabis users.
- Published In:
- Schizophrenia research, 139(1-3), 19-26 (2012)
- Authors:
- Roser, Patrik(9), Lissek, Silke, Tegenthoff, Martin, Nicolas, Volkmar, Juckel, Georg, Brüne, Martin
- Database ID:
- RTHC-00611
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
What is theory of mind?
Theory of mind is the ability to understand that other people have their own thoughts, feelings, and intentions that may differ from yours. It is essential for social interaction, empathy, and communication. Deficits in theory of mind are a core feature of schizophrenia and related disorders.
Does this mean cannabis causes psychosis-like brain changes?
The study found that brain activation patterns in cannabis users resembled those in psychosis-risk populations, but the cross-sectional design cannot prove cannabis caused these changes. It is also possible that people with these pre-existing brain patterns are more likely to become regular cannabis users.
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Cite This Study
https://rethinkthc.com/research/RTHC-00611APA
Roser, Patrik; Lissek, Silke; Tegenthoff, Martin; Nicolas, Volkmar; Juckel, Georg; Brüne, Martin. (2012). Alterations of theory of mind network activation in chronic cannabis users.. Schizophrenia research, 139(1-3), 19-26. https://doi.org/10.1016/j.schres.2012.05.020
MLA
Roser, Patrik, et al. "Alterations of theory of mind network activation in chronic cannabis users.." Schizophrenia research, 2012. https://doi.org/10.1016/j.schres.2012.05.020
RethinkTHC
RethinkTHC Research Database. "Alterations of theory of mind network activation in chronic ..." RTHC-00611. Retrieved from https://rethinkthc.com/research/roser-2012-alterations-of-theory-of
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.