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Does cannabis affect cognitive functioning in patients with schizophrenia?

H. Rachid, Zineb Saif, Salma Raoui, Z. Serhier, Mohamed Agoub

Schizophrenia Research: Cognition December 20, 2023 DOI: 10.1016/j.scog.2023.100299 (opens in new tab)

Study at a glance

AI-extracted from the abstract
Characteristics Cross-sectional observational study Peer reviewed
Sample size 99
Population Moroccan patients diagnosed with schizophrenia (50 cannabis users and 49 non-users) recruited at a university psychiatric centre
Intervention Cannabis use
Measures CogState neuropsychological battery
Topics Cannabis
Key findings Among patients with schizophrenia, cannabis users performed worse on psychomotor function, attention, and verbal memory but better on working memory, visual memory, and emotional recognition than non-users; no group difference was found for executive function. The authors suggest cannabis use may have differing effects across cognitive domains.

Abstract

Introduction: Cannabis use impairs cognitive performance in healthy subjects; several studies have shown improved cognitive outcomes in schizophrenic patients using cannabis. The aim of this study was to evaluate the effects of cannabis use on cognitive function in Moroccan patients with schizophrenia who were cannabis users.

Method: Two groups were recruited in a Moroccan University Psychiatric Centre. Fifty patients diagnosed with schizophrenia according to the DSM-V who were cannabis users (SZ CANN +) and forty-nine patients diagnosed with schizophrenia according to DSM-V who do not use cannabis (SZ CANN-). Cognitive functioning was assessed using the CogState neuropsychological battery.

Results: The results of the study suggest that SZ CANN- patients performed better in the test of psychomotor function, attention and verbal memory. While SZ CANN+ patients performed better in the test of working memory, visual memory and emotional recognition. We found no relationship between SZ CANN+ patients and SZ CANN- patients concerning executive function.

Conclusions: Our results suggest that cannabis use may have different effects on neurocognitive functioning. It is associated with disorders of psychomotor function, attention and verbal memory. So, it is associated with an improvement in working memory, visual memory and emotion recognition.