. 2023 Nov;53(15):7062-7069.

doi: 10.1017/S0033291723000399. Epub 2023 Mar 23.

Cannabis use and psychotic disorders in diverse settings in the Global South: findings from INTREPID II

Joni Lee Pow^{1

2}, Casswina Donald¹, Marta di Forti³, Tessa Roberts^{3

4}, Helen A Weiss⁵, Olatunde Ayinde⁶, Sujit John⁷, Bola Olley⁶, Akin Ojagbemi⁶, Georgina Miguel Esponda^{3

4}, Joseph Lam^{3

4}, Paramasivam Poornachandrika⁸, Paola Dazzan^{9

10}, Fiona Gaughran¹¹, Palaniyandi Ponnusamy Kannan¹², Selvaraju Sudhakar¹³, Jonathan Burns¹⁴, Bonginkosi Chiliza¹⁵; INTREPID Group; Alex Cohen⁵, Oye Gureje⁶, Rangaswamy Thara⁷, Robin M Murray¹¹, Craig Morgan^{3

4

9}, Gerard Hutchinson¹

Affiliations

¹ Department of Psychiatry, University of the West Indies, Saint Augustine, Trinidad.
² Health Service and Population Research Department, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
³ Social, Genetic and Developmental Psychiatry, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
⁴ ESRC Centre for Society and Mental Health, King's College London, London, UK.
⁵ Centre for Global Mental Health, London School of Hygiene & Tropical Medicine, London, UK.
⁶ Department of Psychiatry, WHO Collaborating Centre for Research and Training in Mental Health, Neurosciences and Substance Abuse, University of Ibadan, Ibadan, Nigeria.
⁷ Department of Psychiatry, Schizophrenia Research Foundation, Chennai, India.
⁸ Institute of Mental Health, Madras Medical College, Kilpauk, Chennai, India.
⁹ National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London, London, UK.
¹⁰ Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
¹¹ Psychosis Studies Department, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
¹² Department of Psychiatry, Rajiv Gandhi General Hospital and Madras Medical College, Chennai, India.
¹³ Department of Psychiatry, Chengelpet Medical College, Chengelpet, Tamil Nadu, India.
¹⁴ Mental Health Research Group, College of Medicine and Health, University of Exeter, Exeter, UK.
¹⁵ Department of Psychiatry, University of KwaZulu Natal, Durban, South Africa.

PMID: 36951137
PMCID: PMC10719629
DOI: 10.1017/S0033291723000399

Cannabis use and psychotic disorders in diverse settings in the Global South: findings from INTREPID II

Joni Lee Pow et al. Psychol Med. 2023 Nov.

. 2023 Nov;53(15):7062-7069.

doi: 10.1017/S0033291723000399. Epub 2023 Mar 23.

Authors

Affiliations

¹ Department of Psychiatry, University of the West Indies, Saint Augustine, Trinidad.
² Health Service and Population Research Department, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
³ Social, Genetic and Developmental Psychiatry, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
⁴ ESRC Centre for Society and Mental Health, King's College London, London, UK.
⁵ Centre for Global Mental Health, London School of Hygiene & Tropical Medicine, London, UK.
⁶ Department of Psychiatry, WHO Collaborating Centre for Research and Training in Mental Health, Neurosciences and Substance Abuse, University of Ibadan, Ibadan, Nigeria.
⁷ Department of Psychiatry, Schizophrenia Research Foundation, Chennai, India.
⁸ Institute of Mental Health, Madras Medical College, Kilpauk, Chennai, India.
⁹ National Institute for Health Research (NIHR) Mental Health Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King's College London, London, UK.
¹⁰ Psychological Medicine, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
¹¹ Psychosis Studies Department, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.
¹² Department of Psychiatry, Rajiv Gandhi General Hospital and Madras Medical College, Chennai, India.
¹³ Department of Psychiatry, Chengelpet Medical College, Chengelpet, Tamil Nadu, India.
¹⁴ Mental Health Research Group, College of Medicine and Health, University of Exeter, Exeter, UK.
¹⁵ Department of Psychiatry, University of KwaZulu Natal, Durban, South Africa.

PMID: 36951137
PMCID: PMC10719629
DOI: 10.1017/S0033291723000399

Abstract

Background: Cannabis use has been linked to psychotic disorders but this association has been primarily observed in the Global North. This study investigates patterns of cannabis use and associations with psychoses in three Global South (regions within Latin America, Asia, Africa and Oceania) settings.

Methods: Case-control study within the International Programme of Research on Psychotic Disorders (INTREPID) II conducted between May 2018 and September 2020. In each setting, we recruited over 200 individuals with an untreated psychosis and individually-matched controls (Kancheepuram India; Ibadan, Nigeria; northern Trinidad). Controls, with no past or current psychotic disorder, were individually-matched to cases by 5-year age group, sex and neighbourhood. Presence of psychotic disorder assessed using the Schedules for Clinical Assessment in Neuropsychiatry and cannabis exposure measured by the World Health Organisation Alcohol, Smoking and Substance Involvement Screening Test (ASSIST).

Results: Cases reported higher lifetime and frequent cannabis use than controls in each setting. In Trinidad, cannabis use was associated with increased odds of psychotic disorder: lifetime cannabis use (adj. OR 1.58, 95% CI 0.99-2.53); frequent cannabis use (adj. OR 1.99, 95% CI 1.10-3.60); cannabis dependency (as measured by high ASSIST score) (adj. OR 4.70, 95% CI 1.77-12.47), early age of first use (adj. OR 1.83, 95% CI 1.03-3.27). Cannabis use in the other two settings was too rare to examine associations.

Conclusions: In line with previous studies, we found associations between cannabis use and the occurrence and age of onset of psychoses in Trinidad. These findings have implications for strategies for prevention of psychosis.

Keywords: cannabis; first-onset; global mental health; psychosis; schizophrenia.

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Figures

**Fig. 1.**
(a) Adjusted incidence rates for psychosis in the INTREPID II sites plotted against the prevalence of frequent cannabis use in matched controls and median age of onset of psychosis. (b) Median age of onset of psychosis plotted against the prevalence of frequent cannabis use in matched controls.

See this image and copyright information in PMC

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Cannabis use and psychotic disorders in diverse settings in the Global South: findings from INTREPID II

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Cannabis use and psychotic disorders in diverse settings in the Global South: findings from INTREPID II

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