Suicide Risk in Individuals With Psychiatric Disorder: Population-Based Cohort Study

Objective: We aimed to investigate whether the risks of suicide and non-suicide death vary based on the presence of psychiatric disorders. Methods: Patients diagnosed with psychiatric disorders in South Korea between January 1, 2017, and December 31, 2017, were included and referred to as the psychiatric disorder (PY) group. A comparison group, the non-PY group, included individuals who had never been diagnosed with psychiatric disorders, selected using a 1:1 stratified random sampling technique based on age and sex. The patients were followed up for death by suicide (primary endpoint) from January 1, 2018 to December 31, 2022. All other causes of death were categorized as non-suicidal deaths. Results: After 1:1 propensity score (PS) matching, 761,384 adult participants (380,692 in each group) were finally included. Of these, 0.2% (830/380,692) of individuals in the PY group died by suicide, compared with <0.01% (13/380,692) in the non-PY group. The PY group had a 64.43-fold higher risk of suicide death (hazard ratio [HR]: 64.43, 95% confidence interval [CI]: 37.25–111.43, p<0.001) compared to the non-PY group. Additionally, 8.6% (32,746/380,692) of the PY group died from non-suicidal causes, while 7.1% (27,043/380,692) of the non-PY group died from non-suicidal causes. PY group had a 1.22-fold higher risk of non-suicidal death (HR: 1.22, 95% CI: 1.20–1.24, p<0.001) compared to the non-PY group. Conclusion: Psychiatric disorders were associated with a significantly elevated suicidal risk in South Korea, which was substantially greater than the risk of non-suicidal deaths.