Program for Alleviating and Resolving Trauma and Stress 2

The investigators will conduct a pilot RCT to test the preliminary efficacy of the Program for Alleviating and Resolving Trauma and Stress (PARTS) compared with a Nature-Based Stress Reduction for Trauma Survivors (NBSR-T) control group at reducing PTSD symptom severity measured by Clinician-Administered PTSD Scale (CAPS-5). Secondary clinical outcomes include the effects of the intervention on self-reported PTSD symptoms (PCL-5; CAT-PTSD), disassociation (MDI), and disturbances of self-organization (ITQ). Secondary mechanistic outcomes include emotion regulation (DERS), self-compassion (SCS-SF), and decentering (EQ-D) . Exploratory aims of the study are to investigate the effects on depression (CAT-DI), mental health (CAT-MH scales), self-trauma fusion (PRISM-D), perceived stress (PSS), internalized stigma (ISMI), and interoception (MAIA-2). Additional exploratory outcomes include changes in outcome variables among PTSD subjects with baseline DSO and those without DSO as defined by the International Trauma Questionnaire (ITQ).