Subthreshold posttraumatic stress disorder: A meta-analytic review of DSM-IV prevalence and a proposed DSM-5 approach to measurement.

Subthreshold posttraumatic stress disorder (PTSD) is a chronic condition that is often ignored, the cumulative effects of which can negatively impact an individual's quality of life and overall health care costs. However, subthreshold PTSD prevalence rates and impairment remain unclear due to variations in research methodology. This study examined the existing literature in order to recommend approaches to standardize subthreshold PTSD assessment. We conducted (a) a meta-analysis of subthreshold PTSD prevalence rates and (b) compared functional impairment associated with the 3 most commonly studied subthreshold PTSD definitions. Meta-analytic results revealed that the average prevalence rate of subthreshold PTSD across studies was 14.7%, with a lower rate (12.6%) among the most methodologically rigorous studies and higher rate (15.6%) across less rigorous studies. There were significant methodological differences among reviewed studies with regard to definition, measurement, and population. Different definitions led to prevalence rates ranging between 13.7% and 16.4%. Variability in prevalence rates most related to population and sample composition, with trauma type and community (vs. epidemiological) samples significantly impacting heterogeneity. Qualitative information gathered from studies presenting functional correlates supported current evidence that psychological and behavioral parameters were worse among subthreshold PTSD groups compared with no-PTSD groups, but not as severe as impairment in PTSD groups. Several studies also reported significant increased risk of suicidality and hopelessness as well as higher health care utilization rates among those with subthreshold PTSD (compared with trauma exposed no-PTSD samples). Based on findings, we propose recommendations for developing a standard approach to evaluation of subthreshold PTSD.