Prevalence and prognosis of schizophrenia in Jinuo people in China: A prospective 30-year follow-up study

Background: There are few studies investigating the influence of the development on mental health of minorities in China. Aims: To follow up the prevalence, natural course and prognosis of schizophrenia in Jinuo people, the last group to be recognized as a 'national minority' in China, every 10 years since 1979. Methods: From 1979 to 2009, 15%-19% of Jinuo residents were evaluated by random cluster sampling and followed up every 10 years using the Chinese version of the Composite International Diagnostic Interview (CIDI) as the screening tool and the International Classification of Diseases (ICD) as diagnostic criteria tool. Results: There were no significant differences for the lifetime prevalence and current prevalence of schizophrenia across the three decades. Neither were there any significant differences for the prognosis of schizophrenia; however, at least half the patients had deteriorated or had residual symptoms in the follow-up. PANSS symptoms were significantly different according to different illness duration. Conclusions: During the three decades, there was no increasing trend for schizophrenia prevalence in Jinuo society; however, the prognosis of schizophrenia was not optimistic. In the natural, untreated status, schizophrenia patients with an illness duration of more than 20 years had more serious symptoms.