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Updated: Jun 19, 2026

Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study
Published on: August 18, 2020
Illicit substance use and its correlates in first episode psychosis
R Mazzoncini1, K Donoghue, J Hart
1Department of Medicine and Public Health, University of Verona, Italy. rodolfo.mazzoncini@univr.it <rodolfo.mazzoncini@univr.it>
Objective:
To determine if substance use (particularly cannabis) is more frequent among first episode psychosis patients and associated with a more problematic clinical presentation.
Method:
All first episode psychosis (FEP) patients presenting to secondary services were recruited from London and Nottingham, over 2 years, in the Aetiology and Ethnicity of Schizophrenia and Other Psychoses study broad framework. Clinical and sociodemographic variables were assessed using a set of standardized instruments. A schedule was created to retrospectively collate substance use data from patients, relatives and clinicians.
Results:
Five hundred and eleven FEP were identified. They used three to five times more substances than general population. Substance use was associated with poorer social adjustment and a more acute mode of onset. Cannabis use did not affect social adjustment, but was associated with a more acute mode of onset.
Conclusion:
Cannabis has a different impact on FEP than other substances. Large epidemiological studies are needed to disentangle cannabis effect.
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