This randomized controlled trial will assess whether a novel complementary and alternative medicines (CAM) intervention, Loving-kindness Meditation (LKM), is not meaningfully inferior to another group-based PTSD treatment , Cognitive Processing Therapy (Cognitive Only version; CPT-C) for reductions in PTSD and depressive symptoms. 170 male and female Veterans with current PTSD will be randomized to LKM or CPT-C. The investigators hypothesize that Veterans randomized to LKM will report mean reductions in PTSD and depressive symptom severity that are not meaningfully worse than CPT-C. The investigators further hypothesize that reductions in posttraumatic maladaptive beliefs will more strongly mediate PTSD and depressive symptom improvement for those assigned to CPT-C than those assigned to LKM.

Aim 1: Evaluate if LKM is non-inferior to CPT-C in producing reductions in PTSD symptoms among Veterans with current PTSD. Aim 2: Evaluate the non-inferiority of LKM and CPT-C in producing reductions in depressive symptoms among Veterans with current PTSD. Exploratory Aim: Evaluate potential mediators of response to LKM and to CPT to provide preliminary information regarding whether they are consistent with the mechanisms of change conceptualized by each intervention to be associated with improvement in PTSD and depression.

Methods: A randomized controlled non-inferiority trial comparing LKM to CPT-C. In the proposed project 170 Veterans with PTSD will be randomized to LKM or CPT-C. Comprehensive assessments will be performed at baseline as well as at the end of the 12-week interventions and 3 and 6 months later. PTSD symptoms, depression, posttraumatic maladaptive cognitions and self-compassion will be assessed weekly during the treatment phase to assess temporality of change and to assess mediators of outcomes.

Inclusion Criteria:

• Current Diagnostic and Statistical Manual of Mental Disorder (DSM)-5 diagnosis of PTSD,
• 18 or over,
• English fluency,
• Willingness to not participate in Mindfulness-Based Stress Reduction or other meditation programs, as well as Prolonged Exposure (PE) or CPT during the study period.

Exclusion Criteria:

• Any of the following substance use criteria: 1) Use in the past 90 days of illicit substance (do not include cannabis)/ street drug (non-prescribed); 2) Use in the past 90 days of prescription drug of abuse, use is not as prescribed AND poses safety concern
• Alcohol involvement that poses a safety concern or is associated with inability to follow through on assessments and class attendance as evinced by current drinking AND dt's or seizure in past year
• Suicidal or homicidal ideation with intent or plan
• Attempted harm to Self or others in the past month
• A lifetime psychotic disorder or current psychotic symptoms
• Uncontrolled bipolar disorder (ie current mania, current hypomania is not an exclusion)
• Chart diagnoses of borderline personality disorder or antisocial personality disorder
• In-patient admission for psychiatric reasons within the past month
• Prior participation in LKM or CPT
• Dementia

A de-identified, anonymized dataset will be created and shared.

From baseline to 6-month follow-up (approximately 9 months total).

We prospectively monitored hospitalizations, suicidality and death. In addition we recorded events according to the following criteria: An increase of 20 or more points on the total CAPS-5 score since the last assessment point or an increase in depression severity of 2 or more severity categories using a rubric that transformed PROMIS depression values scores to Patient Health Questionnaire (PHQ)-9 scores and categories

The study involved predominantly male veterans from one facility; the results may not generalize to nonveterans or veterans in other regions. Treatment credibility and adequacy of blinding of the clinician-assessor of PTSD symptoms were not assessed.