Suicide and the unique prevalence pattern of schizophrenia in mainland China: a retrospective observational study

Unlike almost every other country in the world, the prevalence of both schizophrenia and suicide in China is higher in women than in men. Schizophrenia and suicide are important public-health problems for China that might be related to each other. We present prevalence data for schizophrenia and estimate relative and attributable risk of suicide in people with schizophrenia in mainland China.

We used data from the national psychiatric epidemiology study, the Ministry of Health's mortality registry, the census, and the national psychological autopsy study to estimate frequencies and rates of schizophrenia, suicide, and suicide in people with schizophrenia aged 15 years and older in mainland China during 1995-99.

We estimated 4.25 million people with schizophrenia in China, and 284614 suicides and 28737 suicides in people with schizophrenia yearly. Prevalence of schizophrenia was higher in women than men (relative risk 1.77 [95% CI 1.15-2.72]), and greater in urban than rural areas (1.62 [1.10-2.40]). Risk of suicide was greater in women than men (1.22 [1.20-1.23]) and in rural than urban areas (3.61 [3.56-3.66]). Relative risk of suicide in individuals with schizophrenia compared with those without was 23.8 (18.8-30.2); the proportion of all suicides attributable to schizophrenia was 9.7% (7.7-12.1). Relative risk of suicide in rural residents with schizophrenia versus those without was higher in men than in women (ratio of two relative risks 2.02 [1.13-3.63]), but in urban residents with schizophrenia the ratio was lower in men than women (0.56 [0.21-.49]).

Risk factors for suicide vary in people with different mental disorders, so identification of illness-specific risk profiles would improve prediction of suicide and help tailor prevention efforts. The difference in suicide rates by sex and residential location in individuals with schizophrenia might be one of several contributing factors to the unique epidemiological pattern of schizophrenia in China.