Age-stratified risk of suicide in patients with schizophrenia

Objectives: Schizophrenia is associated with an increased risk of suicide. Few studies have investigated the risk of suicide across different ages, likely due to limitations around sample size. Methods: From the National Health Insurance Research Database in Taiwan, this study identified 195,787 patients with schizophrenia from January 1, 2000, to December 31, 2019. During the study period, 3848 patients died from suicide. We calculated the standardized mortality ratio (SMR) for suicide stratified by age. In this age-stratified, nested case–control study, risk set sampling was used to match each case with 4 living controls by age, sex, and the year of the first diagnosis with schizophrenia. Conditional logistic regression was used for estimating age-stratified risk profiles. Results: The SMR was the highest in the <25 years age group (52.8) and inversely correlated with age. Unemployment was associated with an increased risk of suicide in the 25 to 34, 35 to 44, 45 to 54, and 55 to 64 years age groups. Depressive and sleep disorders before suicide were more common among suicide cases with schizophrenia than among controls across all age groups. Drug-induced and alcohol-induced mental disorders were significantly associated with suicide but were observed only in the age group younger than 54. Heart disease, pneumonia, and moderate or severe renal disease were risk factors for suicide in the age groups less than 65. Conclusions: The risk factors for suicide differ by age. This study's findings can be used to optimize health-care interventions for preventing suicide in patients with schizophrenia.