Schizotypy and psychosis-like experiences from recreational cannabis in a non-clinical sample
E. Barkus, S. Lewis
Psychological Medicine September 1, 2008 DOI: 10.1017/s0033291707002619 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 532 |
| Population | Young people who had used cannabis at least once |
| Measures | Cannabis Experiences Questionnaire (CEQ), Schizotypal Personality Questionnaire (SPQ) |
| Topics | Cannabis |
| Key findings | Higher schizotypy was associated with increased psychosis-like experiences and after-effects from cannabis, and also with more pleasurable experiences. Psychosis-like items were most related to schizotypy both during and after cannabis use, suggesting cannabis may reveal vulnerability to psychosis. |
Abstract
BackgroundThe relationship between cannabis use and psychosis is still a matter for debate. Accounting for the individual differences in subjective experiences to recreational cannabis use in the general population may hold some clues to the aetiological relationship between cannabis and psychotic symptoms. We hypothesized that schizotypy would account for the individual differences in subjective experiences after cannabis use but not in patterns of use.MethodIn a sample of 532 young people who had used cannabis at least once, we examined the relationship between the Cannabis Experiences Questionnaire (CEQ) and the Schizotypal Personality Questionnaire (SPQ). Additionally, we examined the psychometric properties of the CEQ.ResultsWe replicated our previously reported findings that schizotypy was associated with increased psychosis-like experiences and after-effects, but also found that high-scoring schizotypes reported more pleasurable experiences when smoking cannabis. Using new subscales derived from principal components analysis (PCA), we found that the psychosis-like items were most related to varying rates of schizotypy both during the immediate use of cannabis and in the after-effects of cannabis use. High-scoring schizotypes who used cannabis experienced more psychosis-like symptoms during and after use.ConclusionsOur results suggest that cannabis use may reveal an underlying vulnerability to psychosis in those with high schizotypal traits.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |
Citations in the library
Cited by 25
- Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment Journal of Psychopharmacology October 5, 2012
- Rates and correlates of cannabis-associated psychotic symptoms in over 230,000 people who use cannabis Translational Psychiatry September 6, 2022
- Salvia divinorum use and phenomenology: results from an online survey. Journal of Psychopharmacology November 1, 2011
- Cognitive mechanisms in cannabis-related paranoia; Initial testing and model proposal Psychosis May 13, 2020
- Does variation in trait schizotypy and frequency of cannabis use influence the acute subjective, cognitive and psychotomimetic effects of delta-9-tetrahydrocannabinol? A mega-analysis Journal of Psychopharmacology January 9, 2021
and 20 more in the library
Cites 8
- Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases The British Journal of Psychiatry November 30, 2005
- Cannabis use and psychotic disorders: an update Drug and Alcohol Review November 30, 2004
- Disturbances of visual information processing in early states of psychosis and experimental delta-9-tetrahydrocannabinol altered states of consciousness. Schizophrenia Research December 1, 2006
- Is Cannabis Use a Contributory Cause of Psychosis? The Canadian Journal of Psychiatry August 1, 2006
- Cannabis-Induced Psychosis-Like Experiences Are Associated with High Schizotypy Psychopathology 2006
and 3 more in the library