A Quasi-Experimental Trial on the Effectiveness of Rational Emotive Behavioural Therapy in Adults with Major Depressive Disorder at a Tertiary Hospital in Lusaka, Zambia

Background Major depressive disorder (MDD) is a prevalent and debilitating condition. Despite the widespread occurrence of the condition, access to available therapeutic options is severely limited in low-income countries. The study aimed at assessing the effectiveness of Rational Emotive Behavioural Therapy (REBT) in managing MDD in adults in a Zambian cultural setting in Lusaka. Methods A quasi-experimental pre-post same group design was employed with repeated assessments over 6 and 12 weeks between August and October 2024. The sample size was estimated using the effect size sampling formula for a pre-post-trial and a total of 30 participants was desired. Participants were interviewed using the Diagnostic and Statistical Manual of Mental Disorders (DSM5), the Becks Depression Inventory (BDI), and the WHO Quality of Life scale (WHOQOL-Brief) at baseline. Rational Emotive Behavioural Therapy (REBT) was then implemented upon ascertaining the participants study eligibility. The generalized Estimating Equation (GEE), paired t-tests, and descriptive statistics were employed in the data analysis. The JASP (0.19) analytical software was utilized to perform the statistical analysis. Results Although the desired sample size was 30, only 28 were willing to participate, giving a 93.3% retention rate. Half (50%) of the participants were aged between 18–25 with only 14% accounting for participants above 40 years. Females made up 64.3% of the total participants and approximately 92.9% of the participants identified as Christians. Thirteen (46.4%) participants had severe depressive symptoms at baseline, with the proportion significantly reducing to 7 (25%; p = 0.031) at 6 weeks of REBT and 0 (0%) after 12 weeks. Majority (71.4%) were experiencing mild symptoms (p < 0.001) after the study period. Physical health and religion were statistically significant (ß = -1.58, 95% CI = -2.24— -0.91, p < 0.001; ß = 3.70, 95% CI = 1.01—6.38, p < 0.001, respectively). Conclusion The study showed REBT to likely lead to a significant reduction in depressive symptoms and thus, could be utilized in the management of MDD.