Acute cannabis use causes increased psychotomimetic experiences in individuals prone to psychosis
O. Mason, C. J. A. Morgan, S. K. Dhiman, A. Patel, N. Parti, Hv Curran
Psychological Medicine June 1, 2009 DOI: 10.1017/s0033291708004741 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 284 |
| Population | Cannabis users and non-using controls |
| Measures | Psychotomimetic States Inventory (PSI), Schizotypal Personality Questionnaire (SPQ) |
| Topics | Cannabis |
| Key findings | Acute cannabis use reliably increased psychotomimetic symptoms, and highly psychosis-prone individuals experienced enhanced psychotomimetic states compared to those low in psychosis proneness. |
Abstract
BackgroundEpidemiological evidence suggests a link between cannabis use and psychosis. A variety of factors have been proposed to mediate an individual's vulnerability to the harmful effects of the drug, one of which is their psychosis proneness. We hypothesized that highly psychosis-prone individuals would report more marked psychotic experiences under the acute influence of cannabis.MethodA group of cannabis users (n=140) completed the Psychotomimetic States Inventory (PSI) once while acutely intoxicated and again when free of cannabis. A control group (n=144) completed the PSI on two parallel test days. All participants also completed a drug history and the Schizotypal Personality Questionnaire (SPQ). Highly psychosis-prone individuals from both groups were then compared with individuals scoring low on psychosis proneness by taking those in each group scoring above and below the upper and lower quartiles using norms for the SPQ.ResultsSmoking cannabis in a naturalistic setting reliably induced marked increases in psychotomimetic symptoms. Consistent with predictions, highly psychosis-prone individuals experienced enhanced psychotomimetic states following acute cannabis use.ConclusionsThese findings suggest that an individual's response to acute cannabis and their psychosis-proneness scores are related and both may be markers of vulnerability to the harmful effects of this drug.
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 26
- The paradoxical psychological effects of lysergic acid diethylamide (LSD) Psychological Medicine February 5, 2016
- The neuropsychopharmacology of cannabis: A review of human imaging studies Pharmacology & Therapeutics October 20, 2018
- Investigating the interaction between schizotypy, divergent thinking and cannabis use Consciousness and Cognition January 10, 2012
- Rates and correlates of cannabis-associated psychotic symptoms in over 230,000 people who use cannabis Translational Psychiatry September 6, 2022
- Cannabis and Psychosis Through the Lens of DSM-5 International Journal of Environmental Research and Public Health October 28, 2019
and 21 more in the library
Cites 8
- Cannabis and schizophrenia: model projections of the impact of the rise in cannabis use on historical and future trends in schizophrenia in England and Wales Addiction February 10, 2007
- Schizotypy and psychosis-like experiences from recreational cannabis in a non-clinical sample Psychological Medicine September 1, 2008
- Blunted psychotomimetic and amnestic effects of delta-9-tetrahydrocannabinol in frequent users of cannabis. Neuropsychopharmacology September 2008
- The psychotomimetic states inventory (PSI): measuring psychotic-type experiences from ketamine and cannabis. Schizophrenia Research August 2008
- Cannabis-Induced Psychosis-Like Experiences Are Associated with High Schizotypy Psychopathology 2006
and 3 more in the library