Cannabis may increase psychosis-like traits by disrupting how the brain assigns importance to things
In 910 university students, cannabis use predicted higher psychosis-like traits, and this relationship was partly explained by aberrant salience, a tendency to assign unusual importance to ordinary stimuli.
Quick Facts
What This Study Found
Among 910 students, frequent cannabis use predicted higher scores on positive and disorganized schizotypy subscales. Mediation analysis showed that aberrant salience (abnormal importance assignment) explained the relationship between cannabis use and specific traits including ideas of reference, odd beliefs, unusual perceptual experiences, and odd speech.
Key Numbers
910 students; frequent cannabis use predicted positive and disorganized schizotypy; aberrant salience mediated the relationship for ideas of reference, odd beliefs, unusual perceptions, and odd speech.
How They Did This
Cross-sectional survey of 910 university students using validated questionnaires for cannabis experience, schizotypal personality traits, psychic experiences, and aberrant salience. Mediation analysis tested whether salience dysfunction explained cannabis-schizotypy links.
Why This Research Matters
The dopamine hypothesis of psychosis centers on aberrant salience. This study provides the first evidence in a non-clinical population that cannabis may promote psychosis-like experiences specifically through disrupting how the brain decides what is important.
The Bigger Picture
This offers a cognitive mechanism linking cannabis to psychosis: cannabis does not just increase psychotic symptoms generally, but may specifically disrupt the brain filter that normally prevents us from over-interpreting random events as meaningful.
What This Study Doesn't Tell Us
Cross-sectional (cannot establish directionality); self-report measures; university sample may not generalize; schizotypy is not the same as clinical psychosis; cannot distinguish cause from predisposition.
Questions This Raises
- ?Does cannabis acutely induce aberrant salience, or does pre-existing salience dysfunction drive cannabis use?
- ?Would CBD counteract THC-induced aberrant salience?
Trust & Context
- Key Stat:
- Aberrant salience mediated the cannabis-schizotypy link for 5 key traits
- Evidence Grade:
- Moderate: large non-clinical sample with mediation analysis, but cross-sectional and self-report.
- Study Age:
- Published 2020.
- Original Title:
- Does cannabis use predict psychometric schizotypy via aberrant salience?
- Published In:
- Schizophrenia research, 220, 194-200 (2020)
- Authors:
- O'Tuathaigh, Colm M P(2), Dawes, Christopher(3), Bickerdike, Andrea(3), Duggan, Eileen, O'Neill, Cian, Waddington, John L, Moran, Paula M
- Database ID:
- RTHC-02752
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
What is aberrant salience?
A tendency to assign unusual importance or meaning to ordinary experiences. It is thought to underlie psychotic symptoms like ideas of reference (feeling everyday events have special personal meaning).
Does cannabis cause psychosis-like thinking?
In this study, cannabis use predicted psychosis-like traits partly through disrupted salience processing. However, the cross-sectional design cannot determine whether cannabis causes the disruption or people with aberrant salience are drawn to cannabis.
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Cite This Study
https://rethinkthc.com/research/RTHC-02752APA
O'Tuathaigh, Colm M P; Dawes, Christopher; Bickerdike, Andrea; Duggan, Eileen; O'Neill, Cian; Waddington, John L; Moran, Paula M. (2020). Does cannabis use predict psychometric schizotypy via aberrant salience?. Schizophrenia research, 220, 194-200. https://doi.org/10.1016/j.schres.2020.03.021
MLA
O'Tuathaigh, Colm M P, et al. "Does cannabis use predict psychometric schizotypy via aberrant salience?." Schizophrenia research, 2020. https://doi.org/10.1016/j.schres.2020.03.021
RethinkTHC
RethinkTHC Research Database. "Does cannabis use predict psychometric schizotypy via aberra..." RTHC-02752. Retrieved from https://rethinkthc.com/research/o-tuathaigh-2020-does-cannabis-use-predict
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.