RESUMO
Background: Despite several studies on the prevalence and pattern of substance use in Nigeria, there is little information on substance use in patients diagnosed with serious mental illness (SMI) such as schizophrenia and bipolar affective disorder (BD).Aim: The aim of the study was to compare the pattern of psychoactive substance use among outpatients with BD and schizophrenia.Setting: The study was conducted in a neuropsychiatric hospital in Nigeria.Methods: Seventy five consecutive patients with a MINI-PLUS diagnosis of BD were compared with an equal number of patients obtained by systematic random sampling with a MINI-PLUS diagnosis of schizophrenia. Results: The respondents with schizophrenia were aged 1859 years (37.2 ± 9.99) and were predominantly young adult (49, 65.3%), men (46, 61.3%), who were never married (38, 50.7%). Overall, lifetime drug use prevalence was 52%, while for current use, overall prevalence was 21.3%. Participants with BD were aged 1863 years (36.7 ± 10.29) and were predominantly young adult (53, 70.7%), women (44, 58.7%), who were married (32, 42.7%), with tertiary education (31, 41.3%). Overall, lifetime drug use prevalence was 46.7%, while current overall prevalence was 17.3%. These rates (lifetime and current) for both diagnostic groups are higher than what was reported by the World Health Organization in the global status report of 2014 (0% 16%). The statistically significant difference between the two diagnostic groups was related to their sociodemographic and clinical variables and psychoactive substance use.Conclusion: Psychoactive substance use remains a burden in the care of patients diagnosed with schizophrenia and BD. Future policies should incorporate routine screening for substance use at the outpatient department with a view to stemming the tide of this menace