Quality of life and its association with current substance use, medication non-adherence and clinical factors of people with schizophrenia in Southwest Ethiopia: a hospital-based cross-sectional study

Abstract Background Schizophrenia was ranked as one of the top ten illnesses contributing to the global burden of disease. But little is known about the quality of life among people with schizophrenia, in particular in low-income countries. This study was aimed to examine the association of quality of life with current substance use, medication non-adherence and clinical factors of people with schizophrenia at Jimma University Medical Center, psychiatry clinic, Southwest Ethiopia. Methods Institution based cross-sectional study design was employed. Study participants were recruited using a systematic random sampling method and a sample fraction of two was used after the first person was identified by the lottery method. we used the World Health Organization Quality of Life Scale-Brief version (WHOQoL-BREF) and 4-item Morisky Medication Adherence Scale (MMAS-4) to assess the quality of life and medication non-adherence respectively. Data about current substance use was assessed by yes/no questions. Descriptive statistics, such as frequency, mean and standard deviations were computed to describe the characteristics of the study population. Data entry was done using EpiData version 3.1 then exported to SPSS statistics version 25 for analysis and analyzed using multiple linear regression. The assumption for linear regression analysis including the presence of a linear relationship between the outcome and predictor variable, the test of normality, collinearity statistics, auto-correlation and homoscedasticity were checked. Un-standardized Beta (β) coefficients with 95% confidence interval (CI) and P-value < 0.05 were computed to assess the level of association and statistical significance in the final multiple linear regression analysis. Result In this study 31.65% of participants were medication non-adherent and total mean scores of quality of life showed a lower level of satisfaction in social relationship domain (10.14 ± 3.12). Our study showed 152(43.3%), 248(70.7%) and 97(27.6%) of respondents had used tobacco, Khat and alcohol atleast once during the past 3 months respectively. Final adjusted multiple regression model showed medication non-adherence has significant negative association with physical domain (beta = − 4.42, p < 0.001), psychological (beta = − 4.49, p < 0.001), social relationships (beta = − 2.29, p < 0.001) and environmental domains (beta = − 4.95, p < 0.001). Treatment duration has significant negative association with psychological domain (beta = − 0.17, p < 0.04), social relationship (beta = − 0.14, p < 0.005), environmental domain (beta = − 0.24, p < 0.02) and overall quality of life (beta = − 0.67, p < 0.02). Having comorbid physical illness has significant negative association with physical domain (beta = − 2.74, p < 0.001), psychological (beta = − 2.13, p < 0.004), social relationships (beta = − 1.25, p < 0.007), environmental domain (beta = − 3.39, p < 0.001) and overall quality of life (beta = − 9.9, p < 0.001). Current tobacco use has significant negative association with physical domain (beta = − 1.16, p < 0.004), psychological (beta = − 1.23, p < 0.001), social relationships (beta = − 0.88, p < 0.001), environmental domains (beta = − 1.98, p < 0.001) and overall quality of life (beta = − 5.73, p < 0.001). Also, current chewing khat has significant negative association with physical domain (beta = − 1.15, p < 0.003), psychological (beta = − 1.58, p < 0.001), environmental domains (beta = − 2.63, p < 0.001) and overall quality of life (beta = − 6.22, p < 0.001). Conclusion The social relationship domain of quality of life has the lowest mean score. Medication non-adherence, treatment duration, having a comorbid physical illness, current tobacco use and current chewing khat were found to have a statistically significant association with the overall quality of life. Therefore, treatments aimed to improve social deficits, medication non-adherence, comorbid physical illness and decrease substance abuse is imperative.