The prevalence and profile of non-affective psychosis in the Nigerian Survey of Mental Health and Wellbeing

This study aimed to estimate the prevalence and correlates of non-affective psychosis among adult Nigerians. It was part of the Nigerian Survey of Mental Health and Wellbeing and was conducted in 8 out of the 22 states in Nigeria, representing about 22% of the national population. Face-to-face interviews with adults aged 18 years and over were administered using the WHO Composite International Diagnostic Interview, version 3 (CIDI.3). Clinical re-appraisal was conducted by clinicians on a subsample of respondents. The CIDI.3 was found to have acceptable agreement with clinician-administered assessments, with kappa values ranging between 0.52 to 0.72, respectively, for narrowly-defined and broad categories of non-affective psychosis. The lifetime prevalence of non-affective psychosis was 2.1%, with visual hallucinations being the most commonly reported symptom and delusions of reference the least. Non-affective psychosis was significantly more common among urban dwellers. Persons with non-affective psychosis were at elevated risk to report both lifetime and 12-month comorbid DSM-IV disorders as well as to experience impairment in basic and instrumental role functioning. Only a minority had received any treatment.