People born during a famine in China were found to have an increased risk of the disorder -- a common form of severe mental illness characterized by hallucinations and delusions, as well as deterioration of social functioning and social withdrawal.

Schizophrenia occurs worldwide with a lifetime risk of approximately 1 percent. Increasingly, it is viewed as a neurodevelopmental disorder with environmental influences during early brain development, including fetal nutritional deficiency, modifying risk.

An earlier study found twice the risk of schizophrenia among children conceived during a food shortage in Holland in 1944-1945. However, the number of cases was small, and the findings were only modestly statistically significant.

Risk More Than Doubled

David St. Clair, MD, PhD, of Shanghai Jiao Tong University, Shanghai, China, and colleagues tested the hypothesis that prenatal exposure to famine would increase the rate of schizophrenia in adult life by examining people who lived through a massive famine in China from 1959-1961.

They examined the risk of schizophrenia in the Wuhu region of Anhui, one of the most affected provinces, comparing rates among those born before, during and after the famine years. The team examined all psychiatric case records for the years 1971 through 2001, extracting clinical and socio-demographic information on patients with schizophrenia.

They found that birth rates (per 1,000) in Anhui decreased approximately 80 percent during the famine years from 28.28 in 1958 and 20.97 in 1959 to 8.61 in 1960 and 11.06 in 1961.

Among those born during the famine years, the risk of developing schizophrenia in later life increased from 0.84 percent in 1959 to 2.15 percent in 1960 and 1.81 percent in 1961. The death-adjusted risk was 2.3 times higher for those born in 1960 and 1.9 times higher for those born in 1961.

"Our study strongly supports the view that prenatal exposure to famine increases the risk of schizophrenia in later life," state the authors.

"Using a much larger sample size with clear evidence of exposure, our findings are internally consistent and almost exactly replicate the Dutch findings," they note.

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

Global or Micronutrient Deficiency?

"The Chinese study, while providing invaluable confirmation of the earlier Dutch work, unfortunately is not able to directly advance understanding of how nutrition may perturb prenatal neural development so as to influence risk for schizophrenia," says Richard Neugebauer, PhD, MPH, of the New York State Psychiatric Institute and Columbia University, New York, in an accompanying editorial.

"The most pressing question from a public health and interventionist perspective is whether the relevant nutritional restriction of interest constitutes a global nutritional deficiency or a specific micronutrient deficiency," Neugebauer points out.

"If the former, the implications of this work are confined largely to developing countries where severe protein-calorie malnutrition is common -- certainly a matter of enormous public health and humanitarian concern in its own right. If the latter, the implications extend to developed and developing countries alike," writes Dr. Neugebauer.