Infectious agents

How are infectious agents related to risk for bipolar disorder?

Exposure to infection is often cited as a risk factor for schizophrenia and has recently been investigated in bipolar disorder. This topic summarises the available evidence for the risk of developing bipolar disorder following exposure to influenza and other infectious agents, both before and after birth. The physiological mechanisms underlying any associations are largely unclear. Please also see the topic in Physical Features on markers for infectious agents in adults with bipolar disorder.

What is the evidence for infectious agents as risk factors for bipolar disorder?

Moderate to low quality evidence suggests a large effect of increased risk of bipolar disorder with exposure to meningitis or tuberculosis in childhood, and a medium-sized effect of lower risk of bipolar disorder with exposure to chicken pox in childhood.

There was a medium to large effect of increased risk of bipolar disorder with exposure to maternal influenza during pregnancy, although when trimesters were analysed separately, the effect remained significant only in the third trimester, and only in one study. There were no associations between risk of bipolar disorder and exposure to maternal urinary tract infections or herpes simplex virus 2.

October 2021

Image: © Andrey Burmakin – Fotolia –

Last updated at: 3:51 pm, 21st April 2022
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Fact Sheet Technical Commentary

NeuRA Libraries

Title Colour Legend:
Green - Topic summary is available.
Orange - Topic summary is being compiled.
Red - Topic summary has no current systematic review available.