A large Swedish study suggests that adverse conditions in the womb may be responsible for at least some cases of schizophrenia, which affects about 2 million people in the United States.
Psychologist Christina Hultman of the University of Uppsala in Sweden and her colleagues used the meticulous Swedish birth registry, which documents 99 percent of all births in the country, to find the prenatal records of patients who were subsequently hospitalized for schizophrenia.
Male babies who developed the disease in childhood or adolescence were three times more likely to have been born underweight and four times more likely to have been born to mothers who bled during pregnancy. Schizophrenia in female babies was also linked to problems during pregnancy, but for unknown reasons the correlation was not as strong as in males.
"Those factors indicate that the environment in the womb was not optimum," says Hultman. One possibility: Problems with the mother's placenta lead to oxygen deprivation that prevents proper brain development.