Among 346 university students, current cannabis users reported higher schizotypy traits and more aberrant salience experiences on self-report measures, but did not show impaired salience processing on an objective laboratory task.
Psychosis researchers, cognitive neuroscientists, and clinicians interested in cannabis-psychosis mechanisms.
Higher subjective aberrant salience but normal objective salience processing
What the researchers found
Current cannabis use was associated with higher "disorganized" and "cognitive-perceptual" schizotypy scores and higher aberrant salience inventory scores. However, neither lifetime nor current cannabis use was associated with abnormal latent inhibition (LI), an objective measure of salience processing. Higher scores on specific aberrant salience subscales ("senses sharpening" and "heightened cognition") did predict decreased LI, regardless of cannabis use.
Why it matters
The disconnect between self-reported aberrant salience (which is higher in cannabis users) and objective salience processing (which is normal) helps clarify the mechanism by which cannabis might increase psychosis risk.
The numbers in context
346 participants. Cannabis users had higher disorganized and cognitive-perceptual SPQ scores and higher total ASI scores. No association between cannabis use and LI performance.
How the study worked
Cross-sectional study of 346 university students who completed the Schizotypal Personality Questionnaire, Aberrant Salience Inventory, Cannabis Experience Questionnaire, and a latent inhibition task. Regression models and Bayesian analyses used.
What this study cannot tell us
Non-clinical university sample. Cross-sectional design. Self-reported cannabis use. LI task may lack sensitivity for detecting subtle impairments. Cannot distinguish acute from chronic cannabis effects.
How to read the evidence
Well-designed cross-sectional study with both subjective and objective measures, but non-clinical sample limits generalizability.
When this study was published
Published in 2022.
The bigger picture
The finding that subjective aberrant salience experiences increase with cannabis use but objective salience processing remains intact in non-clinical populations suggests that cannabis may shift perception and interpretation without fundamentally disrupting the underlying cognitive mechanism.
Questions still open
- Would heavier cannabis users or clinical populations show LI impairments? Does the increased subjective aberrant salience represent a preclinical stage of psychosis risk? Could acute intoxication produce different results?
Common questions
Do cannabis users process information differently?
What does this mean for psychosis risk?
Read the original research
Latent inhibition, aberrant salience, and schizotypy traits in cannabis users.
Schizophrenia research. Cognition, 28, 100235
Citation
Dawes, Christopher; Quinn, Declan; Bickerdike, Andrea; O'Neill, Cian; Granger, Kiri T; Pereira, Sarah Carneiro; Mah, Sue Lynn; Haselgrove, Mark; Waddington, John L; O'Tuathaigh, Colm; Moran, Paula M. (2022). Latent inhibition, aberrant salience, and schizotypy traits in cannabis users.. Schizophrenia research. Cognition, 28, 100235. https://doi.org/10.1016/j.scog.2021.100235
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