Cannabis and psychosis: what is the link?
Mohamed Ben Amar, Stéphane Potvin
Journal of Psychoactive Drugs June 1, 2007 DOI: 10.1080/02791072.2007.10399871 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Systematic review Longitudinal Peer reviewed |
|---|---|
| Topics | Cannabis |
| Key findings | Evidence suggests cannabis use increases the risk of psychotic symptoms, but the causal nature of the association with diagnosed psychosis remains unclear. |
Abstract
Growing evidence supports the hypothesis that cannabis consumption is a risk factor for the development of psychotic symptoms. Nonetheless, controversy remains about the causal nature of the association. This review takes the debate further through a critical appraisal of the evidence. An electronic search was performed, allowing to identify 622 studies published until June 1st 2005. Longitudinal studies and literature reviews were selected if they addressed specifically the issues of the cannabis/psychosis relationship or possible mechanisms involved. Ten epidemiological studies were relevant: three supported a causal relationship between cannabis use and diagnosed psychosis; five suggested that chronic cannabis intake increases the frequency of psychotic symptoms, but not of diagnosed psychosis; and two showed no causal relationship. Potential neurobiological mechanisms were also identified, involving dopamine, endocannabinoids, and brain growth factors. Although there is evidence that cannabis use increases the risk of developing psychotic symptoms, the causal nature of this association remains unclear. Contributing factors include heavy consumption, length and early age of exposure, and psychotic vulnerability. This conclusion should be mitigated by uncertainty arising from cannabis use assessment, psychosis measurement, reverse causality and control of residual confounding.
Comparable studies
Other systematic reviews and meta-analyses on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| Effects of cannabis use on outcomes of psychotic disorders: systematic review People with psychotic disorders, as examined in 13 longitudinal studies | 2008 | Systematic review | |
| The Impact of Cannabis Use on Cognitive Functioning in Patients With Schizophrenia: A Meta-analysis of Existing Findings and New Data in a First-Episode Sample Patients with established schizophrenia (meta-analysis: 572) and patients with... | 2010 | Meta-analysis and cross-sectional observational study | n = 700 |
| Medicinal cannabis for psychiatric disorders: a clinically-focused systematic review | 2020 | Systematic review | |
| Neuroimaging in cannabis use: a systematic review of the literature Cannabis users and controls in neuroimaging studies | 2009 | Systematic review | |
| Human Laboratory Studies on Cannabinoids and Psychosis. Healthy human subjects and individuals with schizophrenia | 2016 | Systematic review |
Citations in the library
Cited by 5
- Risk-thresholds for the association between frequency of cannabis use and the development of psychosis: a systematic review and meta-analysis Psychological Medicine March 24, 2022
- Cannabis and Psychosis: A Review of the Risk Factors Involved American Journal of Plant Sciences 2020
- Brain Changes during Cannabis-Induced Psychosis: Clarifying the Marijuana Medicine/Harm Dichotomy Journal of psychiatry and brain science 2018
- Emergency department presentations related to acute toxicity following recreational use of cannabis products in Switzerland. Drug and Alcohol Dependence 2020
- Cannabis consumption and psychosis or schizophrenia development International Journal of Social Psychiatry November 1, 2018
Cites 15
- Causal association between cannabis and psychosis: examination of the evidence The British Journal of Psychiatry January 30, 2004
- Psychiatric effects of cannabis The British Journal of Psychiatry February 1, 2001
- Exploring the relationship between cannabis use and psychosis Addiction September 15, 2004
- Cannabis and psychosis: accumulating evidence Addiction September 15, 2004
- Schizophrénie et cannabinoïdes Drogues santé et société July 7, 2004
and 10 more in the library