Investigating PTSD, mental disorders, and suicide through self-comparison: a self-controlled case series study over...

Posttraumatic stress disorder (PTSD) significantly impacts mental health and society, yet gaps exist in understanding its temporal relationships with comorbid mental disorders. This study used self-comparison approach to explore the longitudinal relationships between PTSD and comorbid mental disorders, suicide deaths, and all cause of death, identifying risk periods and temporal sequences. A cohort study using the Taiwan National Health Insurance Research Database included adults with incident PTSD diagnosis from 2000 to 2012, followed until 2018 or death. The study employed a self-controlled case series design, and risk period encompasses the present year and five years both preceding and following the incident PTSD diagnosis, with time outside the risk period functioned as a self-controlled period for comparison. Analysis showed reciprocal relationships between PTSD and various mental disorders, especially within the year of or preceding PTSD diagnosis. However, major depressive disorders primarily emerged as a predictor of PTSD. Furthermore, an increased risk of suicide deaths was noted within three to five years post-PTSD, while no association with all cause of death was observed within five years post-PTSD. This study reveals complex, bidirectional relationships between PTSD and several mental disorders, emphasizing the need for integrated treatment and targeted prevention. Immediate attention to PTSD and comorbid mental disorders is crucial, particularly within the first year. The findings provide deeper insights for psychiatric nosology, psychiatric disorder diagnosis, treatment, and prevention.