The equivalence and relative efficacy of psychodynamic psychotherapy and cognitive behavioural therapy for the treatment of adult depressive disorders : a meta-analytic test of active comparison randomized controlled trials

Abstract

Meta-analyses comparing psychodynamic psychotherapy and cognitive-behavioural therapy (CBT) for depressive disorders are limited by heterogeneity in diagnostic samples, comparators, and a lack of equivalence testing. Additionally, extant meta-analyses on psychodynamic psychotherapy and CBT focus on standardized mean differences (SMDs) without examining potential differences in response rates, reliable change, deterioration, and acceptability (i.e., all-cause dropout). Objective: This dissertation addresses these gaps through a meta-analytic test of the equivalence and relative efficacy of psychodynamic psychotherapy and CBT for depressive disorders in the adult general population. Method: A comprehensive literature search across multiple databases using reliable screening methods identified nine active comparison randomized controlled trials (RCTs) directly comparing manualized psychodynamic psychotherapy (N = 572) and CBT (N = 509) for diagnosed depressive disorders in adults. Weighted pooled SMDs (Hedges’ g) were computed, and equivalence testing (g = 0.24) was conducted at post-treatment and follow-up using the two one-sided test procedure. Response rate (i.e., ≥ 50% symptom reduction), reliable change, deterioration, and acceptability were analyzed as event rates and relative risk ratios (RR). For studies that did not report response, reliable change, or deterioration, these values were estimated using a validated imputation method. Results: Independent raters determined that all included studies were of adequate quality. At post-treatment, depressive symptoms were statistically equivalent across psychodynamic psychotherapy and cognitive behavioural therapy (k = 9; g = -0.11, pequivalence = .048, pNHST = .212). At follow-up, the longest time point within a year, depressive symptoms were neither statistically equivalent nor statistically different (k = 6; g = -0.16, pequivalence = .184, pNHST = .126). Rates of response rates, reliable improvement, deterioration, and acceptability did not differ significantly across psychodynamic psychotherapy and CBT. Conclusion: Manualized psychodynamic psychotherapy and CBT demonstrate equivalent efficacy at post-treatment for depressive disorders in adults. However, insufficient data exists to determine equivalence at follow-up. There was no evidence that psychodynamic psychotherapy and CBT differ significantly in rates of response, reliable improvement, deterioration, or acceptability. Likewise, the observed differences between psychodynamic psychotherapy and CBT for reducing symptoms of depression are modest. Accordingly, patient preference should guide treatment selection.Arts, Faculty ofPsychology, Department ofGraduat