The prevalence and clinical impairment of subthreshold PTSD using DSM-5 criteria in a national sample of Korean firefighters

Background Firefighters are at high risk for subthreshold and full-threshold posttraumatic stress disorder (PTSD) due to their frequent exposure to various traumatic events. Although individuals with subthreshold PTSD have increased impairment, often needing treatment, the rates of subthreshold PTSD in firefighters remain unknown. Moreover, there is currently no consensus regarding the definition of subthreshold PTSD. The purpose of this study was to investigate the rates and clinical impairment of subthreshold PTSD according to various definitions in a national sample of firefighters. Methods A total of 45,698 Korean firefighters completed self-reported questionnaires to assess the severity of PTSD symptoms, suicidal behavior, depression, alcohol use problems, and PTS-related functional impairment. Six different definitions used in the literature were used to calculate the prevalence rate of subthreshold PTSD. Multivariable linear regression and analysis of variance were performed to identify the relationship of subthreshold PTSD with suicidal behavior, depression, alcohol use problems, and PTS-related functional impairment. Results The rate of full-threshold PTSD was 2.63%, and the rate of subthreshold PTSD ranged from 1.79% to 17.98%. The individuals with subthreshold PTSD most commonly failed the D criteria, which included negative alterations in cognition and mood. Regardless of the definition used, subthreshold PTSD was found to be associated with increased suicidal behavior, depression, alcohol use problems, and functional impairment. Conclusions Subthreshold PTSD appears to be equal to or more frequent than full-threshold PTSD in Korean firefighters and associated with various negative clinical outcomes. Further effort to detect and treat subthreshold PTSD in firefighters may be essential.