Measuring Dimensions of Posttraumatic Stress Disorder: The Iowa Traumatic Response Inventory

Abstract

Researchers have suggested that the symptoms of posttraumatic stress disorder (PTSD) should be divided into the four dimensions of intrusions, avoidance, numbing or dysphoria, and hyperarousal. However, the clinical utility of a dysphoria/general distress symptom dimension is unclear, and measures of the overall structure of PTSD are limited by the small number of avoidance and prototypical hyperarousal symptoms in the Diagnostic and Statistical Manual of Mental Disorders (DSM). The Iowa Traumatic Response Inventory (ITRI) was created as a broader measure of symptoms related to PTSD. The factor analytic method of test construction was used to create the scales from a larger pool of items. The measure was validated in a clinical sample and in a student sample. Analysis of the ITRI symptom dimensions suggests traumatic intrusions and avoidance symptoms are highly associated and are specific to PTSD, whereas dysphoria, hyperarousal, and dissociation are not specific to PTSD. Overall, the ITRI was found to be a reliable and valid measure of PTSD symptoms that better captures the observed structure of the disorder.