Clinical benefits of self-guided mindfulness coach mobile app use for veterans with posttraumatic stress disorder: A pilot randomized control trial.

Mindfulness training can relieve posttraumatic stress disorder (PTSD) symptoms in military veterans and others but is inconsistently accessible. Self-guided mobile apps could improve access but their acceptability, feasibility, and benefits for veterans with PTSD have not been established. We conducted a pilot randomized trial of Mindfulness Coach (MC), a free, publicly available, trauma-informed mobile app tailored to veterans. U.S. veterans with PTSD (n = 173) were randomized to self-guided use of MC or waitlist control (WLC) with 8-week follow-up. Clinical outcomes were PTSD symptoms (PTSD Symptom Checklist-5), depression symptoms (Patient Health Questionnaire, nine item), and psychosocial functioning (Brief Inventory of Psychosocial Functioning). Primary analyses were intent-to-treat using linear mixed models with maximum likelihood estimation. App uptake, objective usage, and usability ratings measured acceptance and feasibility. Participants varied in age, gender, and ethnoracial identity; most reported recent mental health care utilization. Although study attrition was high (68.4% overall) due to participant dropout (treatment: 43.0%; control: 43.7%) and technical study issues (23% overall), diagnostic tests showed no evidence of bias due to missingness. Study completers (MC: n = 19; WLC: n = 37) showed medium effects on PTSD symptoms (b = -9.31, d = -0.69) and depression (b = -3.10, d = -0.52). Higher-intensity users showed greater benefits. App engagement trended lower for women and minoritized subpopulations. No changes were observed in psychosocial functioning. Usability and helpfulness ratings were favorable. Transdiagnostic clinical benefits indicate promise for MC as a public health resource for veterans with PTSD. Further study is warranted to confirm these benefits and ensure consistent engagement across subpopulations. (PsycInfo Database Record (c) 2025 APA, all rights reserved).