Previously, a Dutch study had suggested that babies born during a food shortage in the mid-1940s in that country were twice as likely as children born during other years to develop schizophrenia. But the conclusion was limited by the study's small sample size. Now David St. Clair of Shanghai Jiao Tong University in China and his colleagues have examined a much larger number of medical records from a psychiatric hospital that serves the Wuhu region of China. Currently home to some three million people, Wuhu had about half that many inhabitants during a massive famine that occurred between 1959 and 1961. The food shortage decreased the birth rate in the area by 80 percent over the course of the two-year catastrophe. From the hospital data the researchers determined the prevalence of schizophrenia in the region between 1971 and 2001 and linked the results to birth year. They found that children born in 1960 had 2.3 times the normal risk of developing schizophrenia. Those born in 1961 faced a risk 1.9 times greater, according to the report.
The results almost exactly replicate the Dutch findings but with a much larger sample size, the authors say, and thus strongly support the hypothesis that prenatal exposure to famine leads to an increased risk of schizophrenia. "Since the two populations are ethnically and culturally distinct," they write, "the processes involved may apply in all populations undergoing famine."