Abstract

This study aimed to translate the Tonic Immobility Scale(TIS), designed to evaluate tonic immobility (TI) reactions following traumatic events, into Korean (K-TIS) and to assess its reliability and validity. Data were gathered from 400 adults throughout South Korea, comprising participants from local communities (n=150) and an online professional survey agency (n=250). Exploratory factor analyses revealed that a one-factor structure was the best fit for the K-TIS across the samples. The total scale exhibited high internal consistency, and the K-TIS demonstrated significant positive correlations with measures of somatoform and psychoform dissociation, supporting its convergent validity. Additionally, TI scores showed significant differences between individuals with and without posttraumatic stress disorder (PTSD) symptoms. Hierarchical logistic regression analyses indicated that TI significantly predicted classification as PTSD or Complex PTSD, even after controlling for somatoform and psychoform dissociation. Overall, these findings suggest that the K-TIS is a reliable and valid tool for assessing tonic immobility as a trauma-related response in adults.