A study of a famine in China more than 40 years ago found that children born to severely malnourished women are more likely to develop schizophrenia (search).

The research bolsters the evidence that environmental factors can trigger the devastating mental illness.

Compared with children born before or after the 1959-61 famine, those born during the disaster faced double the risk of becoming schizophrenic later on.

The results are nearly identical to a previous study of a famine in Holland resulting from a Nazi food blockade toward the end of World War II.

"Since the two populations are ethnically and culturally distinct, the processes involved may apply in all populations undergoing famine," the authors said.

Lead author Dr. David St. Clair of the University of Aberdeen, Scotland, conducted the study with researchers from China. Their findings appear in Wednesday's Journal of the American Medical Association.

The study supports the theory that schizophrenia is caused by a genetic predisposition influenced by environmental triggers that disturb the developing fetal brain -- in this case, nutritional deficiencies.

And that raises the possibility that preventing starvation and malnutrition could head off some cases, said Richard Neugebauer, a schizophrenia researcher at the New York State Psychiatric Institute who was not involved in the study.

Neugebauer said in an accompanying editorial that the study's similarity to the earlier Dutch findings is remarkable given the differences in the two populations.

Still, Neugebauer said, the new research leaves unanswered exactly how nutritional deficiencies disturb fetal brain development to the point of increasing the risk of schizophrenia.

It also does not resolve whether deficiencies in all foods or in a single nutrient increase the risk. That is "the most pressing question from a public health and interventionist perspective," Neugebauer wrote.

The answer would determine whether the findings apply globally or just to developing countries where overall malnutrition is common, he said.

Schizophrenia is characterized by delusional thinking and difficulty in dealing with others. It affects about 1 percent of the world population. Symptoms usually appear during the teens or early adulthood.

Schizophrenia runs in families, and various infections -- including measles, flu and herpes -- are among environmental factors that some scientists believe may increase the risk when they affect pregnant women.

The famine study focused on the Wuhu region of Anhui province in eastern China, one of the hardest-hit areas. The researchers examined data on births and deaths before, during and after the famine and on psychiatric records from 1971 to 2001.

In 1960, in the midst of the famine, there were 13,748 children born in the region; 192 of them developed schizophrenia. That compared with 483 schizophrenics out of 59,088 births in 1956 and 695 out of 83,536 births in 1965.