Bipolar disorder linked to flu during mother's pregnancy


2013-05-11 22:17

A new study found that children born after being exposed to the flu during pregnancy may have a nearly four-fold higher risk of later developing bipolar disorder.

According to the study's lead researcher, the findings cannot prove that a pregnant mother's flu actually causes her child to develop bipolar disorder, but the link does suggest that the mental illness might be preventable.

"The idea is that if influenza is playing a causal role, and we can't say that from one study, there is a vaccine," said Dr. Alan Brown to Reaters Health. Dr. Brown is a professor of psychiatry and epidemiology at Columbia University in New York.

"It's affordable and also I would argue that there are other things that pregnant women could do. For example, hand washing and staying away from people with the flu," he said.

Past studies had already established a link between flu during pregnancy and the offspring's heightened risk of developing schizophrenia, which often involves hallucinations, delusions and paranoia.

Like schizophrenia, bipolar disorder has some similarities. However, it is also different because it includes alternate cycles of mania and depression, even though one type of bipolar diagnosis involves mania alone.

Previous research regarding the association between a child's risk of bipolar disorder and their mother's flu during pregnancy has not been clearly demonstrated, wrote Brown and his colleagues in JAMA Psychiatry.

In this new study, Brown's team searched for a link between flu exposure and children's bipolar in data from a study involving soon-to-be mothers living in Alameda County, California, between 1959 and 1966.

Using the mothers' medical records and follow up information about their children, the researchers had information on 92 children who were exposed to the flu while in the womb, and on 722 who were not.

Of those kids exposed to the flu, approximately 9 percent were diagnosed with bipolar disorder, compared to around 3 percent of those not exposed.

"What we found is that (schizophrenia and bipolar disorder) share at least this in common. Maternal influenza is related to bipolar disorder," Brown said, althought he added that they did not see a connection between bipolar disorder and a mother's common cold or other upper respiratory infections.

According to Brown, until more studies are done, he and his team can only guess at what is behind the associationg between flu and bipolar disorder.

"We think there is an inflammation going on in the fetus due to this infection and it can alter key aspects of brain development and function," Brown said.

SOURCE: JAMA Psychiatry May 8, 2013; doi:10.1001/jamapsychiatry.2013.896