Schizophrenia after prenatal famine. Further evidence.

Suggestive findings of an earlier study that prenatal nutritional deficiency was a determinant of schizophrenia prompted us to undertake a second test of the hypothesis using more precise data on both exposure and outcome. Among persons born in the cities of western Netherlands during 1944 through 1946, we compared the risk for schizophrenia in those exposed and unexposed during early gestation to the Dutch Hunger Winter of 1944/1945. The frequency of hospitalized patients with schizophrenia at age 24 to 48 years in the exposed and unexposed birth cohorts was ascertained from a national psychiatric registry. The most exposed birth cohort, conceived at the height of the famine, showed a twofold and statistically significant increase in the risk for schizophrenia (relative risk [RR] = 2.0; 95% confidence interval [CI] = 1.2 to 3.4; P < .01) in both men (RR = 1.9; 95% CI = 1.0 to 3.7; P = .05) and women (RR = 2.2; 95% CI = 1.0 to 4.7; P = .04). Among all birth cohorts of 1944 through 1946, the risk for schizophrenia clearly peaked in this exposed cohort. Prenatal nutritional deficiency may play a role in the origin of some cases of schizophrenia.