The impact of comorbid personality disorders on the effectiveness of acute phase treatments for depression: a meta-analysis and meta-regression

BACKGROUNDResults from previous meta-analyses of the impact of comorbid personality disorders (PD's) on treatment outcomes for depressive disorder are contradictory and biased by methodological differences between included studies. AIMTo investigate the impact of comorbid PD on the outcome of depression treatments, using only studies with controlled treatments and structured measurement instruments (PROSPERO, CRD42019120200). METHODStudies were searched in PubMed, PsycINFO and Embase, and in reference lists of selected articles and previous meta-analyses. Treatment studies for depression with a subset of individuals with comorbid PD were included. Primary outcome was depression severity change during treatment. Effect sizes were estimated using random effect models, study-level variables were examined with meta-regression. Bias was assessed with the Risk of Bias tool. RESULTSSix studies involving 942 individuals (447 with PD) were included. There was no significant difference in depression severity reduction between individuals with and without PD (g = 0.03, 95% CI -0.15-0.20, p = 0.27). Heterogeneity and risk of bias were low. The meta-regression did not yield significant results. CONCLUSIONFindings don't indicate an impact of comorbid PD on the outcome of acute phase treatment for depression. Depressed patients with and without comorbid PD should receive the same evidence-based depression treatments.