Development of a Subclinical Dissociation Scale by Comparing Healthy Controls with Patients.

We developed a Subclinical Dissociation Scale by comparing healthy controls with patients with post-traumatic stress disorder (PTSD) or dissociative disorder. The Dissociative Experiences Scale, Subclinical Dissociation Scale, and General Health Questionnaire were completed by 441 healthy Japanese adolescents (mean age, 19.9 years) and 23 psychiatric inpatients (mean age, 28.8 years) diagnosed with PTSD or dissociative disorder. The initial Subclinical Dissociation Scale included 52 items grouped into five factors: F1, absentmindedness (14 items); F2, immersion or preoccupation (15 items); F3, temporary amnesia (10 items); F4, feelings of unreality (eight items); and F5, feelings of alienation (five items). Factor and correlation analyses revealed the validity and reliability of the Subclinical Dissociation Scale. The final version of the scale that comprised three factors (F1, F2, and F4) and 37 items underwent logistic regression and receiver operating characteristic (ROC) curve analyses to compare healthy controls with patients with PTSD or dissociative disorder. The ROC curve analysis using the Youden Index indicated a cut-off score of 18 for the borderline or abnormal range, which was calculated using the following formula: "(F1) + (F4) - (F2)." This study provides evidence of the partial test-retest reliability and con current validity of the Subclinical Dissociation Scale.