Posttraumatic Symptom Scale-Interview Version for DSM-5 (PSS-I-5)
The PSS-I-5 is a widely utilized PTSD measure administered by an interviewer. It is a semi-structured interview providing a categorical diagnosis, as well as a measure of the severity of PTSD symptoms as defined by DSM-5. It can be administered by any trained person and takes 15-25 minutes. The PSS-I-5 has been validated for two time intervals: "past two weeks" and "past month."
To access the PSS-I-5 please contact the author directly. This resource should be used in an ethical and responsible manner and should be used only for the purpose(s) for which it has demonstrable validity. Please observe copyright where indicated and reference it appropriately. A manual for administration and scoring of the PSS-I-5 is available.
The PSS-I-5 was first published by Foa et al (2013):
Edna B. Foa, PhD
Center for the Study and Treatment of Anxiety
University of Pennsylvania
3535 Market Street, 6th Floor
Philadelphia, PA 19104
The PSS-I-5 is a 24-item semi-structured interview that assesses PTSD symptoms in the past month and makes a diagnostic determination based upon DSM-5 criteria. The PSS-I-5 begins with a Criterion A trauma screen and identification of an index trauma if multiple events are reported. Questions assess for frequency and intensity of 20 DSM-5 PTSD symptoms. An additional four items ask about distress and interference caused by PTSD symptoms as well as onset and duration of symptoms.
Symptom items are rated on a 5-point scale of frequency and severity ranging from 0 (Not at all) to 4 (6 or more times a week / severe). Symptoms are considered present when rated 1 or higher.
The PSS-I-5 is scored by simply summing the individual item scores. To obtain severity scores for each of the four symptom clusters, sum the items within each cluster. To obtain total PTSD severity, sum all 20 items for a total PTSD symptom severity score, ranging from 0-80. Consistent with the DSM-5, PTSD diagnosis requires the presence of 1 intrusion symptom, 1 avoidance symptom, 2 changes in cognition and mood symptoms, and 2 hyperarousal symptoms. Symptoms must present clinically significant distress or interference, operationalized as a score of 2 or higher on relevant items.
Have you had unwanted distressing memories about the trauma?
0 = Not at all
1 = Once a week or less/a little
2 = 2 to 3 times a week/somewhat
3 = 4 to 5 times a week/very much
4 = 6 or more times a week/severe
The PSS-I-5 has excellent psychometric properties. Inter-rater reliability for PTSD diagnosis (k = .84) and overall severity (r = .98) are excellent (Foa et al., 2016). Internal consistency (alpha = .89) and test-retest reliability (r = .87) were also good (Foa et al., 2016). According to Foa et al., (2016), the PSS-I-5 demonstrated convergent validity with 3 gold standard measures of PTSD, (the CAPS, the PDS-5, and the PCL-IV-Specific Version; all r > .72), and discriminant validity with the Beck Depression Inventory-II, and State-Trait Anxiety Inventory-Trait Scale.
Foa, E. B., McLean, C. P., Zang, Y., Zong, J., Rauch, S., Porter, K., ...& Kauffman, B. (2016). Psychometric properties of the Posttraumatic Stress Disorder Symptoms Scale Interview for DSM-5 (PSSI-5). Psychological Assessment, 28, 1159-1165. doi:10.1037/pas0000259
Information about training and using the PSS-I-5 can be obtained from Edna B. Foa, Center for the Study and Treatment of Anxiety.