Mortality in Patients with Schizophrenia in Japan

Purpose: Patients with schizophrenia have a higher mortality risk than the general population. However, no recent studies have investigated mortality in people with schizophrenia in Japan. Therefore, we conducted a retrospective study to evaluate excess mortalityand risk factors for mortality in patients with schizophrenia in Japan. Methods: : We included patients diagnosed with schizophrenia or schizoaffective disorder at Yamanashi Prefectural Kita Hospital between January 1, 2013, and December 31, 2017. Standardized mortality ratios were used to compare mortality rates between patients with schizophrenia and the general population. Logistic regression analysis was performed to estimate risk factors associated with mortality. Results: : Of the 1,699 patients with schizophrenia (893 men and 806 women), 104 (55 men and 49 women) died during the study period. The all-cause standardized mortality ratio (95% confidential interval [CI]) was 2.25 (1.81–2.68); the natural- and unnatural-cause standardized mortality ratios were 2.09 (1.64–2.54) and 4.68 (2.63–6.74), respectively. Male sex (odds ratio [OR] = 2.24, 95% CI = 1.10–4.56), age (OR = 1.12, 95% CI = 1.09–1.16), and barbiturate use (OR = 8.17, 95% CI = 2.07–32.32) were associated with a high risk of mortality. Conclusion: The mortality rate remains high in patients with schizophrenia in Japan. Further studies are needed to evaluate mortality trends in this population.