Program for Alleviating and Resolving Trauma and Stress 1

The investigators will conduct a single-arm pilot study to test the preliminary efficacy of a virtually delivered, live-online 16-week group model of Internal Family Systems (IFS) for individuals with PTSD, called the PARTS program, on PTSD symptoms measured by Clinician-Administered PTSD Scale (CAPS-5). Secondary outcomes include feasibility and acceptability of the PARTS program measured by a Credibility/Expectancy Questionnaire (CEQ) and Treatment Satisfaction Questionnaire. Secondary clinical outcomes include the effects of the PARTS program on self-report PTSD and disturbances of self-organization (DSO). Exploratory aims of the study are to investigate the effects on emotion regulation (DERS), self-trauma fusion (iPRISM-trauma), disassociation (MDI), depression (CAT-DI), self-compassion (SCS-SF), perceived stress (PSS), mindfulness (TMS), and interception (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).