Psychometric Properties of the UCLA PTSD Reaction Index. Part II: Investigating Factor Structure Findings in a National Clinic-Referred Youth Sample

We examined the underlying factor structure of the UCLA PTSD Reaction Index (PTSD-RI) using data from 6,591 children/adolescents exposed to trauma, presenting for treatment at any of 54 National Child Traumatic Stress Network (NCTSN) centers. Using confirmatory factor analysis, we tested the 3-factor DSM-IV PTSD model, 2 separate 4-factor models (Dysphoria vs. Emotional Numbing) and a recently conceptualized 5-factor Dysphoric Arousal model. We found a slight, but significant advantage for the Dysphoria model over the Emotional Numbing model on the PTSD-RI, with a difference in Bayesian information criterion (BIC) values of 81 points. As with several recent studies of adult trauma victims, we found a slight advantage for the Dysphoric Arousal model over the other models on the PTSD-RI, with BIC differences exceeding 300 points. Retaining the Dysphoric Arousal model, we tested the convergent validity of the PTSD-RI factors against subscales of the Trauma Symptom Checklist for Children. Supporting the convergent validity of the PTSD-RI, in the Dysphoric Arousal model, the dysphoric arousal factor related most strongly to anger, whereas the emotional numbing factor related most strongly to depression, and anxious arousal factor related most strongly to anxiety. Results support the use of the PTSD-RI for evaluating PTSD among youth.