The proposed study is a randomized, controlled trial that will assess whether two group interventions for PTSD - Mindfulness-Based Stress Reduction (MBSR) and Cognitive Processing Therapy-Cognitive only (CPT-C) result in similar improvements in PTSD symptoms and health-related quality of life (QOL). One hundred fifty-two Veterans with PTSD will be randomized to MBSR (n = 76) or CPT-C (n = 76). Comprehensive assessments will take place post-treatment and 3 months later.

The proposed study is a randomized, controlled non-inferiority trial that will assess whether Mindfulness-Based Stress Reduction (MBSR) and Cognitive Processing Therapy-Cognitive only (CPT-C) result in equivalent improvement in both PTSD symptoms and health-related quality of life (QOL). PTSD symptoms will be measured by the Clinician Administered PTSD Scale - CAPS and health-related QOL will be measured by the SF-36V Mental Component Summary Score - MCS. In an exploratory aim, we will also assess whether there is a clinically meaningful response as defined by improvement in both PTSD symptoms and QOL (defined as a reliable change of 12 points on the CAPS and 10 points on the MCS, respectively, according to the reliable change index).7, 8 One hundred fifty-two Veterans with PTSD will be randomized to MBSR (n = 76) or CPT-C (n = 76). Comprehensive assessments will take place post-treatment and 3 months later. Qualitative analysis of brief semi-structured interview data will be used to identify previously unrecognized factors pertaining to participation, adherence and response to treatment, spirituality and religion as treatment moderators, and to identify common themes that may inform treatment retention efforts for both MBSR and CPT-C. In addition, potential moderators of change in PTSD symptoms and QOL for MBSR and CPT-C will be identified.

Inclusion Criteria:

• Veterans with current DSM-V diagnosis of PTSD

Exclusion Criteria:

• Current substance use disorder other than alcohol,
• Alcohol involvement that poses a safety concern or is associated with inability to follow through on assessments and class attendance as evinced by past month appointment attendance record in CPRS,
• Suicidal or homicidal ideation with intent or plan within the past 3 months,
• Self harm in the past 3 months,
• A psychotic disorder,
• Uncontrolled bipolar disorder,
• Chart diagnoses of borderline personality disorder or antisocial personality disorder,
• In-patient admission for psychiatric reasons within the past month,
• Prior participation in MBSR or CPT.