Sex differences in treatment outcomes among U.S. service members with comorbid PTSD and MDD

BACKGROUND: Posttraumatic stress disorder (PTSD) and major depressive disorder (MDD) are prevalent and deleterious conditions that commonly co-occur among service members. Identifying factors such as sex that could be linked to treatment response among service members with these conditions is critical for improving care delivery. METHODS: This study examined sex differences in treatment outcomes among U.S. active duty service members with comorbid PTSD and MDD (N = 94; 55% women, 45% men) in a randomized controlled trial comparing behavioral activation-enhanced cognitive processing therapy (BA + CPT) and standard CPT. PTSD and MDD symptom severity was assessed at pretreatment, posttreatment, and 3-month follow-up. RESULTS: Intent-to-treat multilevel models indicated treatment condition moderated the relationship between sex and PTSD symptoms (p = .020) but not depression (p = .16). On average, Clinician-Administered PTSD Scale for DSM-5 scores decreased significantly more among servicewomen who received CPT versus BA + CPT at posttreatment (p = .004) and 3-month follow-up (p = .049). There were no significant differences in outcomes among servicemen (ps > 0.05). In CPT, servicewomen reported significantly greater PTSD symptom reduction compared to servicemen at posttreatment (p = .039) but not at follow-up (p = .088). In BA + CPT, PTSD symptoms did not significantly differ between sexes at posttreatment (p = .054) or follow-up (p = .29). CONCLUSIONS: Findings suggest sex may differentially impact outcomes for CPT but not BA + CPT among service members with PTSD and MDD and could help inform shared decision-making between patients and providers. TRIAL REGISTRATION: ClinicalTrials.gov registry; registration number NCT02874131; date of registration: 08-22-2016.