A randomized controlled trial of an online group-based internal family systems treatment for posttraumatic stress disorder: The Program for Alleviating and Resolving Trauma and Stress (PARTS) study.

OBJECTIVE: Group-based posttraumatic stress disorder (PTSD) treatment options are in high demand, especially at community health centers with limited staff and resources. We have developed an online telehealth-based, 16-week group psychotherapeutic intervention program called Program for Alleviating and Resolving Trauma and Stress (PARTS) based on the Internal Family Systems psychotherapy framework. The goal of this study is to test the feasibility, acceptability, and preliminary efficacy of PARTS through a randomized controlled trial.

METHOD: This randomized controlled trial randomized patients with PTSD (N = 60) to PARTS (n = 30) or a well-matched active control condition called Nature-Based Stress Reduction for Trauma Survivors, with each arm receiving 16 weekly group sessions and eight biweekly individual counseling sessions. The two arms were compared on intervention adherence, treatment satisfaction, and PTSD symptom changes as measured by the Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders, fifth edition.

RESULTS: Overall, patients in the PARTS arm attended more group sessions compared to the control arm and reported higher levels of group satisfaction (p < .05). Both treatment arms showed statistically significant reduction of Clinician-Administered PTSD Scale for Diagnostic and Statistical Manual of Mental Disorders, fifth edition scores (p < .001) without significant differences between the two treatment arms.

CONCLUSIONS: This study demonstrated the feasibility and acceptability of PARTS as a group-based PTSD treatment. (PsycInfo Database Record (c) 2026 APA, all rights reserved).