The Effect of Concurrent Depression on PTSD Outcomes in Trauma-Focused Psychotherapy: A Meta-Analysis of Randomized Controlled Trials

The co-occurrence of depression with posttraumatic stress disorder (PTSD) is common and associated with greater severity and impairment than PTSD alone, but the effects on PTSD treatment outcomes are unclear. This study investigated the impact of baseline depression on PTSD symptom change and dropout in a meta-analysis of 44 randomized controlled trials (N = 4,866) of trauma-focused psychotherapies for PTSD.
 
Analyses included 107 active (k = 71) and control (k = 36) conditions. Baseline depression was indexed within samples as (a) continuous symptom severity (e.g.,Beck Depression Inventory), standardized across depression measures and (b) proportion of patients with comorbid depressive disorder diagnosis. Among active conditions reporting continuous depression scores (k = 62), greater depression severity predicted smaller PTSD treatment effect sizes (ß = -.36, p = .002), but not dropout (ß = .25, p = .18).
 
Categorical depressive diagnosis rates (k = 29)—reported less frequently—were not associated with treatment effects or dropout in active conditions. Greater depression severity may reflect a risk factor for attenuated response in PTSD psychotherapies, potentially demanding complementary strategies within trauma-focused interventions. Variability between trials in baseline depression symptoms may suggest the need to consider this sample characteristic when comparing treatment outcomes across studies.
 Keywords: PTSD; meta-analysis; depression; comorbidity; psychotherapy.