Schizophrenia, more common in men than in women in most parts of the world, is more prevalent in women in China, suggesting several external factors can play a part in the mental illness, scientists said on Friday.

The research, published in the journal The Lancet, shows social, economic or cultural causes can contribute to schizophrenia in addition to genetics.

The researchers, led by Dr Michael Phillips of China’s Beijing Hui Long Guan Hospital, used census data and information from the Ministry of Health and other sources to estimate that 4.25 million people in China suffer from schizophrenia.

Unlike in other parts of the world, most Chinese schizophrenics were women.

Dr Mao-Sheng Ran, of the University of Hong Kong, said the research challenges the assumption that schizophrenia has a uniform prevalence worldwide with only minor variations.

“Indeed the different cultural, social and economic characteristics of communities could influence the onset and course of schizophrenia,” he said in a commentary.

The researchers also detected a link between schizophrenia and suicide. Nearly 10 percent of the 285,000 deaths from suicide in China each year are in people suffering from schizophrenia the researchers concluded.

Those who commit suicide are also more likely to be women then men.

“Our high estimate of annual suicide deaths in people with schizophrenia in China indicates that this is a major public health problem for the country that will require development of suicide-prevention strategies specifically designed for people with schizophrenia,” Phillips wrote.

SOURCE: The Lancet, September 18, 2004.