September 1977

Seasonality of Schizophrenic Births in the United States

Author Affiliations

From the Richardson Division, St Elizabeths Hospital, Washington, DC (Dr Torrey); the Office of Management and Budget, Washington, DC (Ms Torrey); and the Division of Virology, Bureau of Biologics, Food and Drug Administration, Washington, DC (Dr Peterson).

Arch Gen Psychiatry. 1977;34(9):1065-1070. doi:10.1001/archpsyc.1977.01770210079007

• The birth months of persons later diagnosed as schizophrenic were studied. Data were collected from 19 states on 53,584 schizophrenics born between 1920 and 1955. The controls were the general births in the same states for the same years. A highly significant peak in schizophrenic births was found from December to May, most marked in March and April. The seasonality was stronger in New England and the Midwest than in the South. Previous studies of schizophrenic births are also reviewed. The cumulative evidence would appear to establish more firmly a winter and spring seasonality of schizophrenic births in northern Europe and the eastern United States. Selection of patients, nutritional factors, environmental factors, genetic factors, and infectious agents are discussed as possible etiological explanations.