Examining various subthreshold definitions of PTSD using the Clinician Administered PTSD Scale for DSM-5

Background: The Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5; American Psychiatric Association [APA], 2013) includes Other-and Unspecified-Trauma and Stressor-Related Disorders to capture subthreshold Posttraumatic Stress Disorder (PTSD) symptoms. However, the DSM-5 does not specify the number or type of symptoms needed to assign them. The purpose of the current study was to extend our understanding of subthreshold PTSD by comparing four commonly used definitions adapted to the DSM-5 PTSD criteria in an outpatient treatment-seeking sample. Methods: Veterans (N = 193) presenting to PTSD clinics were assessed using the Clinician Administered PTSD Scale for DSM-5 (CAPS-5). Participants reported a criterion A traumatic event, but did not meet criteria for threshold-PTSD. We hypothesized that the number of veterans captured would be highest when fewer specific criterion sets were required by the subthreshold definition. Results: Our hypothesis was upheld in that the more criteria required by the subthreshold PTSD definition, the lower the number of veterans counted within the group. Limitations: The study consisted primarily of trauma treatment-seeking male veterans, with chronic PTSD symptoms. In addition, the sample size was small and was collected as part of routine clinical care. Conclusions: These results support previous contentions around careful decision making when defining what constitutes subthreshold PTSD in research and clinical work. It also points to the need for continued research to better understand the diagnostic and treatment implications of subthreshold PTSD.