Original Research

Cannabis use and abuse correlates in a homogenous South African schizophrenia population

Liezl Koen, Regan Jonathan, Dana JH Niehaus
South African Journal of Psychiatry | Vol 15, No 1 | a99 | DOI: https://doi.org/10.4102/sajpsychiatry.v15i1.99 | © 2009 Liezl Koen, Regan Jonathan, Dana JH Niehaus | This work is licensed under CC Attribution 4.0
Submitted: 07 August 2008 | Published: 01 March 2009

About the author(s)

Liezl Koen, Dept of Psychiatry, University of Stellenbosch
Regan Jonathan, Dept of Psychiatry, University of Stellenbosch
Dana JH Niehaus, Dept of Psychiatry, University of Stellenbosch

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Objective. Worldwide, cannabis is the most widely used illicit substance, and it has been identified as a correlate in schizophrenia samples for poorer symptomatic and functional outcomes in many international studies. The object of this retrospective study was to identify the prevalence of cannabis use/abuse and the demographic and clinical correlates therefor in a large homogeneous South African schizophrenia population.

Methods. As part of a large genetic study, 547 subjects with a diagnosis of schizophrenia were recruited. Demographic and clinical data were collected and each participant underwent a urinary drug screen. Use/abuse of cannabis was defined as using cannabis more than 21 times in a single year. Subjects with and without cannabis use/abuse were statistically compared.

Results. Significant differences between the two groups were found in terms of gender, marital status, age of onset of schizophrenia, number of hospitalisations and relapses, alcohol abuse, smoking, the Scale for the Assessment of Positive Symptoms (SAPS) scores for hallucinations, delusions, bizarre behaviour and formal thought disorder, and the Scale for the Assessment of Negative Symptoms (SANS) score for avolition/apathy.

Conclusion. The prevalence of cannabis use/abuse in this study was high, and our findings were comparable with those of previous international studies. Abuse/use started mainly in the teenage years, was more prevalent among males than females, and was associated with negative overall outcomes. There was also a positive correlation between cannabis and nicotine and alcohol use/abuse. Determination of cannabis abuse based solely on history was found to be reliable, and urine cannabis testing appeared to be of limited value in routine management of this group of schizophrenic patients.


Cannabis, Schizophrenia


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Crossref Citations

1. Association between formal thought disorder and cannabis use: a systematic review and meta-analysis
Mathilde Argote, Guillaume Sescousse, Jérôme Brunelin, Eric Fakra, Mikail Nourredine, Benjamin Rolland
Schizophrenia  vol: 8  issue: 1  year: 2022  
doi: 10.1038/s41537-022-00286-0