Incidence and prediction of psychiatric morbidity after a motor vehicle accident in Japan: The Tachikawa Cohort of Motor Vehicle Accident Study

Objectives: To assess both the incidence of new-onset psychiatric illness after involvement in a motor vehicle accident in Japan for comparison with Western data and the predictors of psychiatric morbidity and posttraumatic stress disorder (PTSD) evaluated immediately after the accident. Design, Prospective cohort study of injured patients assessed immediately and 4-6 wks after involvement in a motor vehicle accident. Setting. Intensive care unit in a teaching hospital in Tokyo, Japan. Patients. Total of 100 consecutive patients with motor vehicle accident-related injuries (mean Injury Severity Score, 11.2; mean Glasgow Coma Scale, 14.5; age, 18-69 yrs) admitted to the intensive care unit. Patients with traumatic brain injury, suicidality, current psychiatric or neurologic illness, or cognitive impairment were excluded. Measurements. An extensive clinical interview and evaluation of vital signs, sociodemographic variables, previous traumatic events, family history of psychopathology, Impact of Event Scale-Revised, Hospital Anxiety and Depression Scale, Clinician-Administered PTSD Scale, and Mini-International Neuropsychiatric Interview. Results: A total of 31 patients showed some form of new-onset psychiatric illness at the 4- to 1 follow-up. The majority of illnesses consisted of depression (major depression, n = 16; minor depression, n = 7) and PTSD (full PTSD, n = 8; partial PTSD, n 16). Other illnesses included alcohol dependence (n 3), obsessive-compulsive disorder (n = 2), agoraphobia (n = 2), and social phobia (n = 1). Both psychiatric morbidity and PTSD were predicted by a sense of life threat (odds ratio, 4.2 and 6.2, respectively), elevated heart rate (odds ratio, 1.6 and 1.7), and higher Impact of Event Scale-Revised intrusion subscale score (odds ratio, 1.1 and 1.1). Conclusion: This study showed that psychopathology and PTSD after a motor vehicle accident in Japan is common and that the incidence is within the range of that in Western countries. A combination of a sense of life threat, heart rate, and Impact of Event Scale-Revised intrusion subscale allowed for significant prediction of psychiatric morbidity and PTSD.