A brief measure of posttraumatic nightmares
Previous research on nightmares rarely distinguished between posttraumatic and idiopathic nightmares perhaps due to a lack of efficient, psychometrically sound self-report measures. The current study describes the development and preliminary examination of the Posttraumatic Nightmare Index (PTNI), a brief measure to assess the incidence of posttraumatic nightmares. In a sample of 135 university students the scale possessed adequate internal consistency reliability and a unidimensional factor structure. Convergent validity was supported through significant positive correlations with nightmare frequency, nightmare distress, general psychological distress, and posttraumatic stress symptoms. Incremental validity was supported by the PTNI’s ability to uniquely predict trauma symptoms after accounting for nightmare frequency and nightmare frequency after controlling for trauma symptoms. The scale was found to account for its own unique variance after controlling general nightmare frequency. The results and areas for future research were discussed.