Is cannabis use a contributory cause of psychosis?

Degenhardt, Louisa. and Hall, Wayne. (2006) Is cannabis use a contributory cause of psychosis?. Canadian Journal of Psychiatry-Revue Canadienne De Psychiatrie, 51 9: 556-565.

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Author Degenhardt, Louisa.
Hall, Wayne.
Title Is cannabis use a contributory cause of psychosis?
Journal name Canadian Journal of Psychiatry-Revue Canadienne De Psychiatrie   Check publisher's open access policy
ISSN 0706-7437
Publication date 2006-08
Sub-type Critical review of research, literature review, critical commentary
Open Access Status File (Publisher version)
Volume 51
Issue 9
Start page 556
End page 565
Total pages 10
Editor Joel Paris
Place of publication Ottawa, Canada
Publisher Canadian Psychiatric Association
Collection year 2006
Language eng
Subject C1
321202 Epidemiology
730205 Substance abuse
111706 Epidemiology
1117 Public Health and Health Services
Abstract Objective: To assess whether cannabis use in adolescence and young adulthood is a contributory cause of schizophreniform psychosis in that it may precipitate psychosis in vulnerable individuals. Method: We reviewed longitudinal studies of adolescents and young adults that examined the relations between self-reported cannabis use and the risk of diagnosis with a psychosis or of reporting psychotic symptoms. We also reviewed studies that controlled for potential confounders, such as other forms of drug use and personal characteristics that predict an increased risk of psychosis. We assessed evidence for the biological plausibility of a contributory causal relation. Results: Evidence from 6 longitudinal studies in 5 countries shows that regular cannabis use predicts an increased risk of a schizophrenia diagnosis or of reporting symptoms of psychosis. These relations persisted after controlling for confounding variables, such as personal characteristics and other drug use. The relation did not seem to be a result of cannabis use to self-medicate symptoms of psychosis. A contributory causal relation is biologically plausible because psychotic disorders involve disturbances in the dopamine neurotransmitter systems with which the cannabinoid system interacts, as demonstrated by animal studies and one human provocation study. Conclusion: It is most plausible that cannabis use precipitates schizophrenia in individuals who are vulnerable because of a personal or family history of schizophrenia.
Keyword Cannabis
Drug-induced psychosis
Substance use disorders
Severe mental-illness
Environment interaction
Adult psychosis
Onset psychosis
Q-Index Code C1
Institutional Status UQ

Document type: Journal Article
Sub-type: Critical review of research, literature review, critical commentary
Collections: Excellence in Research Australia (ERA) - Collection
2007 Higher Education Research Data Collection
School of Public Health Publications
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Citation counts: TR Web of Science Citation Count  Cited 66 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 15 Aug 2007, 08:51:55 EST