Prevalence of cannabis use in people with psychosis in KwaZulu-Natal, South Africa

Background: There is a high prevalence of cannabis use in patients with schizophrenia spectrum and other psychotic disorders, with comorbid cannabis use in this population being associated with poorer long-term outcomes.Aim: To determine the prevalence of cannabis use in patients with a schizophrenia spectrum and other psychotic disorders.Setting: The study was conducted at a psychiatric hospital in Durban, KwaZulu-Natal Province, South Africa. Methods: A review of clinical records of patients admitted to the hospital for the period, June 2018 to June 2020, was conducted.Results: A total of 370 clinical records were reviewed, of which 48.9% reported current and 51.1% lifetime cannabis use. Being male was significantly associated with current and lifetime cannabis use (OR = 4.90, 95% CI 2.49-9.62 and OR = 6.27, 95% CI 3.28-11.95, respectively). Current alcohol use was also associated with current cannabis use (CCU) (OR = 3.06, 95% CI 1.78-5.28), and age 45 years and older was associated with a lower odds of cannabis use (OR = 0.30, 95% CI 0.09-0.96). Forty-eight per cent of participants were admitted three or more times, and readmission was associated with cannabis use (p = 0.01). There was a lack of association between cannabis use, readmission and human immunodeficiency virus (HIV) status, after controlling for variables such as alcohol use and gender.Conclusion: Almost 50% of people admitted with schizophrenia spectrum and other psychotic disorders have comorbid current and lifetime cannabis use. There is a need for dual diagnosis units to address comorbid substance use in people with psychotic disorders, as it leads to poorer outcomes.