The Posttraumatic Stress Diagnostic Scale (PDS) is a 49-item self-report measure designed to assess all the DSM-IV diagnostic criteria for PTSD.22,23 The PDS, which is based on the self-report counterpart of the PSS-I (PSS-SR) is the only stand-alone instrument that assesses all DSM-IV criteria.18 It was designed as a screening instrument to identify PTSD in the general population or in a population of trauma survivors. The PDS is psychometrically sound.23
There is strong internal consistency and good test-retest reliability across the 17 symptom items of the PDS.22 The PDS correlates well with self-report measures of PTSD, depression, and anxiety. The PDS total severity score and the total number of symptoms endorsed significantly discriminate persons with and without a PTSD diagnosis based on the SCID PTSD module. The PDS has adequate diagnostic utility against the SCID.
The PDS was developed with careful attention to content validity. It yields both a continuous measure of symptom severity and a PTSD diagnosis, and it has excellent psychometric properties. The PDS has been translated into numerous languages and its psychometric properties, which were examined in several cultures, replicate those found in the original study.
The PTSD Checklist (PCL) is a 17-item self-report measure of PTSD developed at the National Center for PTSD in 1990.24 The 17 PCL items correspond to the 17 DSM-IV symptoms of PTSD. Respondents rate how much they have been bothered by each symptom during the past month using a 5-point scale. The PCL yields a continuous measure of PTSD symptom severity for each of the 3 symptom clusters and for the whole syndrome.
The PCL has been widely adopted (especially by Veterans Administration systems) and extensively evaluated, and it has excellent psychometric properties across a variety of trauma populations.24-26 The PCL also correlates strongly with other measures of PTSD and combat exposure, and it has demonstrated good diagnostic utility against the SCID PTSD module.
The Davidson Trauma Scale (DTS) is another 17-item self-report measure that assesses DSM-IV diagnostic criteria for PTSD.27 The format is similar to that of the CAPS in that the frequency and severity of each symptom is rated on separate 4-point scales. The time frame for ratings is the past week. This allows for frequent administrations, which is valuable in treatment outcome studies but limits the use of the DTS as a diagnostic measure.
The DTS appears to have good psychometric properties.27 It has high internal consistency and strong test-retest reliability. It also demonstrates good convergent and discriminant validity and correlates strongly with several other PTSD measures. In addition, the DTS distinguishes between PTSD severity, and it is sensitive to changes in PTSD severity as a function of treatment. Finally, the DTS demonstrates good diagnostic utility against the SCID PTSD module.
The DTS appears to be a useful measure of PTSD. It is well suited for tracking changes in symptom severity in treatment outcome studies and has been widely adopted for this purpose.28 One limitation is that little additional psychometric work has been conducted, so it is not clear how well the original findings can be generalized to other samples and settings.
Developed before the formal recognition of PTSD as a mental disorder in DSM-III, the Impact of Event Scale (IES) is the oldest standardized measure of posttraumatic symptoms.29 Weiss and Marmar30 developed a 22-item revised version (IES-R) by adding 6 hyperarousal items and 1 dissociative item and by changing the response dimension from symptom frequency to degree of subjective distress, expanding the number of response options from 4 to 5 and relabeling the anchors. The IES-R demonstrates the same high level of reliability and validity as the original IES.31 Both versions can be used effectively to assess trauma-related symptoms.
The Mississippi Scale for Combat-Related PTSD (Mississippi Scale) is a 35-item self-report measure of PTSD symptoms and associated features.32 Items are rated on a 5-point scale with anchors that vary according to item content. The Mississippi Scale is the most widely used measure of combat-related PTSD. It has excellent psychometric properties and was selected as the primary PTSD measure in the National Vietnam Veterans Readjustment Study (NVVRS).6,32-35