Effectiveness of an Intensive Experiential Group Therapy Program in Promoting Mental Health and Well-Being Among Mass Shooting Survivors: A Practice-Based Pilot Study

Public Significance Statement The findings of this study suggest that intensive experiential group therapy may be a suitable treatment approach for supporting the mental health and well-being of people who have survived mass shooting episodes. This longitudinal intervention study examines the effectiveness of a 6-day intensive experiential group therapy program for survivors of mass shootings. The sample consisted of 36 participants (83.33% female; M (age) = 41.66, SD (age) = 22.52) who survived a mass shooting episode in the U.S. Self-reported mental health (i.e., PTSD, depression, and anxiety symptoms), physical health (i.e., sleep disturbance, subjective health complaints), and flourishing were assessed at baseline (T0), end of treatment (T1), 1-month follow-up (T2), 3-month follow-up (T3), and 6-month follow-up (T4). Satisfaction with the treatment was evaluated at T1. After controlling for relevant sociodemographic characteristics, multilevel modeling results revealed significant improvements in PTSD (d = -0.86, p < .001), depression (d = -0.76, p < .001), anxiety (d = -0.89, p < .001), and flourishing (d = 0.52, p = .003) at T1. There was weak evidence in support of an improvement in sleep disturbance from T0 to T1 (d = -0.30, p = .054), and the reduction in subjective health complaints was negligible (d = -0.03, p = .847). Posttreatment gains were largely maintained at T2 through T4, with some fluctuations and further gains evidenced over time. Treatment satisfaction ratings at the end of treatment were high. The findings of this practice-based study provide preliminary evidence demonstrating the medium-term effectiveness of a group experiential treatment in promoting the mental health and well-being of mass shooting survivors.