Clinical Summary
Clinical Summary: Major Depressive Disorder and PTSD Treatment Outcome in Interpersonal Psychotherapy and Prolonged Exposure
Many veterans with PTSD also have major depressive disorder, and that comorbidity can complicate treatment choice when trauma-focused therapy is hard to tolerate or less effective. This study asks a practical question clinicians face every day: whether comorbid MDD changes retention and PTSD outcomes differently in prolonged exposure versus interpersonal psychotherapy.
Design
a 2-site, single-blinded RCT (ClinicalTrials.gov NCTO2586064) comparing IPT and PE for the treatment of military-related PTSD in veterans
N
109 (58 IPT, 51 PE) started treatment
Population
male and female veterans who experienced trauma while deployed to a war zone, met DSM-5 criteria for current PTSD with a minimum CAPS for DSM-5 (CAPS-5) symptom severity level of 23, and had at least 1 area of relationship dysfunction
Duration
12 weekly 50-minute sessions
Key Findings
- Overall noncompletion was substantially lower in IPT than in PE: 22.4% for IPT compared to 52.9% for PE; across all participants, those in IPT completed significantly more treatment sessions (χ=9.8) than those in PE (χ=7.1) (t=3.66, P<.001).
- Among veterans without MDD, noncompletion was significantly more likely in PE (63%) than in IPT (18%) (χ2 =12.35, P<.001), and PE patients without MDD completed fewer sessions on average than IPT patients without MDD (6.2 vs 10.2) (P<.001).
- Within PE, veterans with MDD improved significantly less than those without MDD in PTSD symptom severity (t30=−2.16, P =.04) and were significantly less likely to achieve loss of PTSD diagnosis (χ2 =3.86, P =.049) and remission (χ2 =4.57, P =.033).
- Within IPT, MDD status did not distinguish treatment retention or PTSD outcome: 27% of those with MDD and 18% of those without MDD completed fewer than 8 sessions, and those with and without MDD did not differ in amount of change in CAPS-5 symptom severity.
- Among veterans with MDD, IPT showed a clinically meaningful but nonsignificant advantage over PE on PTSD outcomes, with a higher response rate (48% vs 19%) and a trend toward greater improvement in PTSD symptom severity (t = 1.90, P = .07); PHQ-9 change did not differ significantly between IPT and PE.
Clinical Bottom Line
For veterans with PTSD and comorbid MDD, prolonged exposure was associated with poorer PTSD improvement, while interpersonal psychotherapy appeared less affected by depression status. When MDD is present, IPT is a reasonable non-trauma-focused option, especially if concern about PE tolerability or response is high.
Practice Implications
- Assess current MDD before choosing PTSD psychotherapy, because in PE, comorbid MDD was linked to significantly less CAPS-5 improvement and lower rates of loss of diagnosis and remission.
- Discuss retention realistically when offering PE to veterans, given the overall noncompletion rate of 52.9% versus 22.4% for IPT and the especially high 63% noncompletion rate in PE among those without MDD.
- Consider IPT when treating PTSD with comorbid MDD, since PTSD outcomes within IPT did not differ by MDD status and response among patients with MDD was 48% in IPT versus 19% in PE.
- Do not expect IPT to outperform PE specifically on self-reported depression symptom change based on this study, because PHQ-9 improvement did not differ significantly between treatments in patients with or without MDD.
