Herpes in Pregnancy Linked To Schizophrenia in Offspring

First, there were significantly more IgG- and IgM-type antibodies in the blood of the mothers of the case subjects than in the blood of the mothers of the control subjects, the researchers found. This result suggested that the mothers of the former had been infected with some agent at the time they gave birth since the presence of IgG and IgM antibodies in one’s blood suggests systemic infection.

Second, there were significantly more IgG antibodies to herpes simplex virus type 2 in the blood taken from the mothers of case subjects than in the blood taken from the mothers of control subjects, the scientists discovered. This finding implied that maternal infection with herpes simplex virus type 2 might play a role in schizophrenia. In contrast, when blood samples from the two groups were compared for levels of antibodies to the other infectious agents of interest, no significant differences were found. The agents included those that cause chlamydia, cold sores, genital warts, rubella, toxoplasmosis, and viral pneumonia. This finding suggested that these viruses and bacteria are not implicated in schizophrenia.

The investigators then re-analyzed their data, taking into consideration factors that might have distorted their initial appraisal, such as maternal and paternal income, educational level, maternal mental illness, weight gain during pregnancy, or smoking during pregnancy. Their results remained unchanged; all of the associations that they had initially found remained statistically significant.

Thus, “the offspring of mothers with elevated levels of total IgG and IgM immunoglobulins and antibodies to herpes simplex virus type 2 are at increased risk for the development of schizophrenia and other psychotic illnesses in adulthood,” Buka and his team concluded in their study report.

“These are important findings,” S. Hossein Fatemi, M.D., Ph.D., an associate professor of psychiatry, cell biology, and neuroanatomy at the University of Minnesota Medical School and a schizophrenia-virus investigator, told Psychiatric News. The results, he explained, “support previous epidemiological reports linking maternal viral infection with increased risk of developing psychosis in the adult offspring. Additionally, animal experiments conducted in our laboratory. . .for the past four years show that prenatal human influenza viral infection on day nine of pregnancy in mice (approximately early mid-gestation) causes abnormal brain development. . .and abnormal behavior in the developing offspring. . . . It is conceivable that, in the genetically susceptible individual, prenatal viral infection may lead to increased risk for development of a neurodevelopmental disorder like schizophrenia.”

The study by Buka and his colleagues was funded by the Stanley Foundation and the National Institute of Mental Health.