Mortality in patients with schizophrenia in Japan

Patients with schizophrenia have a higher mortality risk than the general population. However, no recent studies have investigated mortality in patients with schizophrenia in Japan. Therefore, we conducted a retrospective study to evaluate excess mortality and risk factors for mortality in patients with schizophrenia in Japan.

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 (SMRs) 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.

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 SMR (95% confidence interval [CI]) was 2.18 (1.76–2.60); the natural- and unnatural-cause SMRs were 2.06 (1.62–2.50) and 5.07 (2.85–7.30), respectively. Men (adjusted odds ratio [OR] = 2.24, 95% CI = 1.10–4.56), age (adjusted OR = 1.12, 95% CI = 1.09–1.16), and barbiturate use (adjusted OR = 8.17, 95% CI = 2.07–32.32) were associated with the risk of mortality.

The mortality rate remains high in patients with schizophrenia in Japan. Further studies are needed to evaluate mortality trends in this population.