Incidence and Prediction of Post-Traumatic Stress Disorder at 6 Months After Motor Vehicle Accidents in Japan

Background: Incidence proportion of post-traumatic stress disorder (PTSD) after motor vehicle accidents (MVA) vary considerably across countries, and whether heart rate (HR) and respiratory rate (RR) immediately after MVA predict subsequent PTSD remains controversial. This study examined the incidence proportion of PTSD at 6 months after MVA in Japan, and the predictors of PTSD in MVA survivors. Method: Patients with MVA-related injuries consecutively admitted to the intensive care unit of a teaching hospital in Tokyo were recruited. Six months after MVA, PTSD was diagnosed using the Clinician Administered Post-traumatic Stress Disorder Scale (CAPS). Results: Of the 300 participants, 106 completed the assessments at 6 months after MVA and PTSD was diagnosed in 7.5% of the patients. Eight of the 300 participants (2.7%) were regarded as having PTSD after imputing their CAPS score at follow-up assessment for participants who dropped out. In multivariate regression analysis, no variables were shown to be independent predictors for PTSD. HR and RR did not predict PTSD in the analysis. Discussion: The results suggested that the incidence proportion of PTSD following MVA in Japan was lower than that in most developed countries, and HR and RR might not be accurate screening tools despite their importance in a fear-conditioning model of the genesis of PTSD.