Event-related PTSD symptoms as a high-risk factor for suicide: longitudinal observational study

There is long-standing controversy as to whether suicide risk in those who have survived a traumatic event is highest when the severity of the survivors’ psychiatric condition is worst or when they begin to recover. To tackle this problem, we extracted psychiatric conditions from an online cohort of Japanese participants during the COVID-19 pandemic, at five time points (T1–T5). For 12,578 responses from 3,815 participants (mean age 47.1 years; 46.8% women), 3,508 psychiatric conditions were extracted in T1, 2,680 in T2, 2,562 in T3, 2,022 in T4 and 1,806 in T5. We then investigated whether extracted conditions could predict suicide rates in the full Japanese population in a time-specific manner. We found that COVID-19-related PTSD symptoms are associated with increased suicide rates ( P = 3.0 × 10 −6 , Bayesian information criterion (BIC) = −23.69), and are of greater concern than depression ( P = 7.6 × 10 −4 , BIC = −13.19) and anxiety symptoms ( P = 5.9 × 10 −3 , BIC = −9.35). Furthermore, associations of psychiatric states with increased suicide rates are time specific ( P = 0.011), suggesting that a population shows higher suicide risk when symptom severity is high. Event-related PTSD symptoms may help to identify groups at high risk of suicide and improve prevention policies.