Assessment of a new self-rating scale for posttraumatic stress disorder

Background. In post-traumatic stress disorder (PTSD) there is a need for self-rating scales that are sensitive to treatment effects and have been tested in a broad range of trauma survivors. Separate measures of frequency and severity may also provide an advantage. Methods. Three hundred and fifty-three men and women completed the Davidson Trauma Scale (DTS), a 17-item scale measuring each DSM-IV symptom of PTSD on 5-point frequency and severity scales. These subjects comprised war veterans, survivors of rape or hurricane and a mixed trauma group participating in a clinical trial. Other scales were included as validity checks as follows: Global ratings, SCL-90-R, Eysenck Scale, Impact of Event Scale and Structured Clinical Interview for DSM-III-R. Results. The scale demonstrated good test-retest reliability (r = 0.86), internal consistency (r = 0.99). One main factor emerged for severity and a smaller one for intrusion. In PTSD diagnosed subjects, and the factor structure more closely resembled the traditional grouping of symptoms. Concurrent validity was obtained against the SCID, with a diagnostic accuracy of 83 % at a DTS score of 40. Good convergent and divergent validity was obtained. The DTS showed predictive validity against response to treatment, as well as being sensitive to treatment effects. Conclusions. The DTS showed good reliability and validity, and offers promised as a scale which is particularly suited to assessing symptom severity, treatment outcome and in screening for the likely diagnosis of PTSD.