Tonic immobility triggered by COVID-19-related trauma is associated with long-term PTSD symptoms

During the COVID-19 pandemic healthcare workers were repeatedly exposed to traumatic experiences. Facing life-threatening events and repeated exposure to traumatic duty-related situations may cause posttraumatic stress disorder (PTSD). While tonic immobility has been considered a key vulnerability factor for PTSD, little is known about this relationship in the long term. In this study, we aimed to determine whether peritraumatic tonic immobility triggered by COVID-19-related trauma predicts PTSD symptom severity six to twelve months later. We conducted an online longitudinal survey using the PTSD Checklist for the DSM-5 (PCL-5) and the Tonic Immobility Scale to assess PTSD symptoms and the tonic immobility response, respectively. Multivariate regression models revealed a significant association between tonic immobility and PTSD symptoms. Each one-unit increase in the tonic immobility score was associated with a 1.5 % increase in the average PTSD symptom score six to twelve months after the traumatic event that triggered the tonic immobility. Furthermore, participants who showed significant or extreme levels of tonic immobility were 3.5 times or 7.3 times more likely to have a probable PTSD diagnosis, respectively. Hence, peritraumatic tonic immobility seems to have a lasting deleterious effect on mental health. Psychological treatment for health care professionals is urgent, and psychoeducation about the involuntary, biological nature of tonic immobility is essential to reduce suffering.