Efficacy of a brief web-based tonic immobility psychoeducation intervention among trauma-exposed adults: A randomized clinical trial.

Tonic immobility (TI) is a defensive response that may occur during traumatic events. Although TI is adaptive in certain circumstances, it has been shown to contribute to increased trauma-related symptoms and poorer recovery. However, current frontline treatments for posttraumatic stress disorder (PTSD) have not focused significant attention on the experience of TI. Thus, the aim of this study was to develop and test the impact of a brief TI-focused psychoeducation (TIP) intervention on posttraumatic cognitions and PTSD symptoms relative to a health education control intervention. The sample included 46 adults with elevated PTSD symptoms who endorsed prior TI episodes. After providing informed consent, participants were randomly assigned to either the active or control intervention and completed self-report questionnaires including the tonic immobility questionnaire (TIQ-R), Life Events Checklist for DSM-5 (LEC-5), Posttraumatic Stress Checklist for DSM-5 (PCL-5), Posttraumatic Cognitions Inventory (PTCI), and Positive and Negative Affect Schedule (PANAS) at baseline, 1-week, and 1-month follow-up assessments. Results from linear mixed effects models indicated that participants in the TIP condition reported significantly larger reductions in posttraumatic cognitions and PTSD symptoms at 1-week, ds = 0.48 and 0.84, respectively, and 1-month, ds = 0.67 and 0.74. The findings suggest that TIP is a promising intervention that may be used to reduce posttraumatic cognitions and PTSD symptoms associated with TI. Given the ease of access, TIP could be used as a standalone intervention or as an add-on to existing evidence-based treatments for PTSD.