This study is a randomized controlled trial comparing an integrated treatment, Behavioral Activation + Cognitive Processing Therapy (BA + CPT), to CPT alone among active-duty service members with posttraumatic stress disorder (PTSD) and comorbid major depressive disorder (MDD). Participants will complete assessor-administered and self-report measures at pre- and post-treatment assessments, as well as a 3-month follow-up. Additionally, participants will complete self-report measures of PTSD and MDD symptoms at each therapy session.

Major depressive disorder (MDD) is the psychological condition most commonly comorbid with posttraumatic stress disorder (PTSD). PTSD and MDD comorbidity is associated with greater symptom severity, lower levels of functioning, greater disability, and increased suicide potential relative to PTSD or MDD alone. Unfortunately, no psychological treatment intervention specifically addresses this comorbidity. Individuals with comorbid PTSD and MDD often receive evidence-based treatments for PTSD, such as cognitive processing therapy (CPT); although such treatments typically reduce both PTSD and depression symptoms, few studies have specifically examined these outcomes in individuals with PTSD and comorbid MDD. The primary goal of this randomized controlled trial is to evaluate whether greater improvement in depression symptoms can be achieved by augmenting CPT with behavioral activation (BA), a standard depression treatment, for active-duty service members with PTSD and comorbid MDD. Participants will be evaluated at three assessment time-points (pre-treatment, post-treatment, and three-month follow-up), as well as complete self-report measures of PTSD and MDD symptoms at each therapy session.

Inclusion Criteria:

• Active-duty service member seeking mental health treatment at Naval Medical Center San Diego (NMCSD), branch clinics, or Naval Hospital Camp Pendleton (NHCP)
• Meet current diagnostic criteria for PTSD based on the DSM-5 as a consequence of any index traumatic event (e.g., combat, military sexual trauma, child abuse, accidents, etc.)
• Meet current diagnostic criteria for MDD based on DSM-5 criteria.

Exclusion Criteria:

• Unmanaged psychosis or manic episode in the past year
• Substance use disorder warranting primary substance use treatment or detoxification
• Participation in concurrent psychotherapies directly targeting PTSD
• Participation in concurrent psychotherapies directly targeting depression

Data will be available only in aggregate