Digital Exposure Therapy to Reduce Posttraumatic Stress Disorder Symptoms After Critical Illness: A Pilot Feasibility Study

BACKGROUND: Posttraumatic stress disorder (PTSD) is common after critical illness. Therapist-delivered exposure therapy is a first-line treatment, but often inaccessible due to cost, limited therapist availability, and perceived stigma. Mobile app-delivered exposure therapy may help address these barriers. Messy Memories is a novel smartphone app that guides patients through core exposure therapy techniques, including self-directed processing of prior distressing experiences. We evaluated the feasibility, acceptability, safety, and potential clinical impact of Messy Memories among critical illness survivors. METHODS: This single-arm feasibility trial was conducted from October 2023 to September 2024. Patients were recruited from U.S. academic medical centers and online platforms. Eligibility criteria included age ≥18 years, intensive care unit (ICU) admission ≥30 days prior to study enrollment, elevated ICU-related PTSD symptoms (i.e., baseline PTSD Checklist [PCL-5] score ≥10), access to an internet-equipped smartphone, and English proficiency. Patients used the Messy Memories app over 6 weeks, during which they received psychoeducation and guided processing of traumatic ICU memories through user-recorded audio exercises. Psychological symptoms, health behaviors, and implementation outcomes were assessed using validated questionnaires and qualitative feedback at 0, 3, 6, and 12 weeks. RESULTS: We enrolled 25 patients (mean age 38±12 years, 56% female, 52% Black, 12% Hispanic, 56% college graduates), of whom 22 (88%) completed the 3-week assessment, 19 (76%) completed the 6-week assessment, and 20 (80%) completed the 12-week assessment. Patients logged into the app a mean of 8.20±7.74 times, and 19 (76%) patients recorded at least one memory (mean 2.58±1.95 memories/patient). Mean PCL-5 score improved from 37.8±13.8 at baseline to 21.4±16.1 at 12 weeks (p < 0.01; Cohen's d = 1.13, 95% CI 0.55-1.71). The proportion of patients meeting criteria for probable PTSD decreased from 64% at baseline to 20% after 12 weeks (p = 0.02), and 55% of patients experienced a clinically significant reduction in PCL-5 score from baseline to 12 weeks. The app was rated as highly feasible, acceptable, and appropriate. No serious adverse events occurred. CONCLUSIONS: Our findings suggest that Messy Memories is feasible, acceptable, and shows promise for reducing PTSD symptoms after critical illness. Further testing is warranted to determine its efficacy in well-powered randomized trials.