Adherence to medication for the treatment of psychosis: rates and risk factors in an Ethiopian population

BACKGROUND: Medication-taking behavior, specifically non-adherence, is significantly associated with treatment outcome and is a major cause of relapse in the treatment of psychotic disorders. Non-adherence can be multifactorial; however, the rates and associated risk factors in an Ethiopian population have not yet been elucidated. The principal aim of this study was to evaluate adherence rates to antipsychotic medications, and secondarily to identify potential factors associated with non-adherence, among psychotic patients at tertiary care teaching hospital in Southwest Ethiopia. METHODS: A cross-sectional study was conducted over a 2-month period in 2009 (January 15(th) to March 20(th)) at the Jimma University Specialized Hospital. Adherence was computed using both a compliant fill rate method and self-reporting via a structured patient interview (focusing on how often regular medication doses were missed altogether, and whether they missed taking their doses on time). Data were analyzed using SPSS for windows version 16.0, and chi-square and Pearsons r tests were used to determine the statistical significance of the association of variables with adherence. RESULT: Three hundred thirty six patients were included in the study. A total of 75.6% were diagnosed with schizophrenia, while the others were diagnosed with other psychotic disorders. Most (88.1%) patients were taking only antipsychotics, while the remainder took more than one medication. Based upon the compliant fill rate, 57.5% of prescription fills were considered compliant, but only 19.6% of participants had compliant fills for all of their prescriptions. In contrast, on the basis of patients self-report, 52.1% of patients reported that they had never missed a medication dose, 32.0% sometimes missed their daily doses, 22.0% only missed taking their dose at the specific scheduled time, and 5.9% missed both taking their dose at the specific scheduled time and sometimes missed their daily doses. The most common reasons provided for missing medication doses were: forgetfulness (36.2%); being busy (21.0%); and a lack of sufficient information about the medication (10.0%). Pill burden, medication side-effects, social drug use, and duration of maintenance therapy each had a statistically significant association with medication adherence (P ≤ 0.05). CONCLUSION: The observed rate of antipsychotic medication adherence in this study was low, and depending upon the definition used to determine adherence, it is either consistent or low compared to previous reports, which highlights its pervasive and problematic nature. Adherence must therefore be considered when planning treatment strategies with antipsychotic medications, particularly in countries such as Ethiopia.