Medication-related factors of non adherence among patients with schizophrenia and bipolar disorder: Outcome of a cross-sectional survey in Maiduguri, North-eastern Nigeria

Pharmacotherapy is the cornerstone in the symptomatic treatment of schizophrenia and bipolar disorder, but non-adherence to the medications constitutes major obstacles to optimal outcome in their management. This study assessed the prevalence of and exclusively x-rayed medication-related factors of non-adherence among patients with these disorders in a resource-poor setting. Three hundred and fifty eight (358) patients with schizophrenia and bipolar disorder were randomly enrolled and interviewed at the out-patient department of the Federal Neuropsychiatric Hospital, Maiduguri in North-eastern Nigeria. Data were collected using an anonymous sociodemographic questionnaire, clinical proforma and the Hausa version of the 8-item Morisky Medication Adherence Scale (MMAS-8). The overall prevalence of non-adherence was 54.2%, while the rates were 62.5% and 45.8% for subjects with schizophrenia and bipolar disorder respectively. The independent medication-related predictors of non-adherence were: multiple dosing frequency (Odds Ratio (O.R) = 7.843, 95% C.I = 4.537 to 13.557, P ≤ 0.001), presence of side effects (O.R = 6.823, 95% C.I = 3.900 - 11.937, p ≤ 0.001), cost of medications (O.R. = 4.009, 95% C.I = 2.555 to 6.921, p ≤ 0.001), and polytherapy (O.R. = 2.317, 95% C.I = 1.363 to 3.940, p = 0.002). This study therefore, recommends the use of guidelines that encourage rational pharmacotherapy based on monotherapy, consider routine lower dosing prescriptions, and integrating side effects surveillance and early intervention in clinical practice. Key words: Non-adherence, schizophrenia, bipolar disorder, North-eastern Nigeria.