Summer births linked to schizophrenia

Young people who develop a severe form of schizophrenia are strikingly likely to have been born in the summer, according to data collected in six countries. Symptoms of the condition, sometimes referred to as deficit schizophrenia, include a lack of emotion, apathy, and an inability to handle social and work situations. In contrast, nondeficit schizophrenia typically includes intense emotions and suicidal thoughts.

Brian Kirkpatrick of the Maryland Psychiatric Research Center in Baltimore and his colleagues unveiled the suggestive correlation after pooling findings from nine studies conducted in England, France, Ireland, Scotland, Spain, and the United States. Those investigations included 1,594 people who had been diagnosed with schizophrenia. Of that number, 401 displayed deficit schizophrenia, Kirkpatrick’s group determined.

A greater percentage of people with deficit schizophrenia was born in June and July compared with the portion of people with nondeficit schizophrenia or of people in the general population born in those two months, the researchers report in the October Archives of General Psychiatry. The finding raises the possibility that summer-related infections or other seasonal factors could be disturbing brain development, the scientists say.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.