Comparisons of Subthreshold Versus Full Posttraumatic Stress Disorder Distinguished by Subjective Functional Impairment Among Train Drivers: A Population-Based Nationwide Study in South Korea

OBJECTIVE: Subthreshold posttraumatic stress disorder (SPTSD), a condition that meets the full symptomatic criteria of posttraumatic stress disorder (PTSD) without subjective functional impairment, has yet to be fully investigated. In this study, we aimed to determine the prevalence and characteristics of SPTSD. METHODS: The web-based survey including psychiatric diagnosis and experience of human error was conducted in actively working train drivers in South Korea. RESULTS: Of the 4,634 subjects, 103 (2.23%) were categorized as full PTSD and 322 (6.96%) were categorized as having SPTSD. Individuals with full PTSD showed higher impulsivity and anxiety compared to those with SPTSD and those without PTSD, while those with SPTSD had more frequent clinically meaningful depression, posttraumatic stress, and alcohol and nicotine dependence and significant human error. CONCLUSION: Despite not qualifying as a subjective functional disability, SPTSD still had significant psychiatric symptoms. More clinical attentions need to be given to the diagnosis and treatment of SPTSD.