When mothers contract influenza during their pregnancy, it may increase the risk for schizophrenia in their offspring, reports the journal Biological Psychiatry. Now, a new study suggests that the observed association depends upon a pre-existing vulnerability in the fetus. Dr. Lauren Ellman, who is affiliated with Columbia University and Temple University, determined that fetal exposure to influenza leads to cognitive problems at age 7 among children who later develop a psychotic disorder in adulthood, but fetal exposure to influenza does not lead to cognitive problems among children who do not later develop a psychotic disorder. Importantly, these findings were dependent upon the type of influenza. The association was only present after fetal exposure to influenza B, as opposed to influenza A.
The new study suggests that a genetic and/or an additional environmental factor associated with psychosis is probably necessary for the fetal brain to be vulnerable to the effects of influenza, given that decreases in cognitive performance were only observed in influenza-exposed children who developed a psychotic disorder in adulthood.
"The good news is that most fetuses exposed to influenza virus while in the womb will not go on to develop schizophrenia. The bad news is that the prior association between influenza infection and later development of psychotic disorders was supported," commented John Krystal, editor of Biological Psychiatry.
This finding may influence efforts to develop prevention, early intervention and treatment strategies; such as taking steps to maintain careful hygiene and, if clinically appropriate, administration of the influenza vaccination to reduce infection among women prior to pregnancy.
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Source: Biological Psychiatry
