Prenatal Inflammation, Infections and Mental Disorders.

BACKGROUND: The objective of this descriptive review is to summarize the current scientific evidence on the effect of prenatal exposure to maternal infection and immune response on the offspring's risk for mental disorders (schizophrenia spectrum disorders, autism spectrum disorders, attention-deficit hyperactivity disorder, anorexia nervosa, and mood disorders). SAMPLING AND METHODS: Studies were searched from PubMed and Ovid MEDLINE (R) databases with the following keywords: 'prenatal exposure delayed effects' and 'infection', and 'inflammation' and 'mental disorders'. A comprehensive manual search, including a search from the reference list of included articles, was also performed.
RESULTS: Prenatal exposure to maternal influenza appears to increase the offspring's risk for schizophrenia spectrum disorders, although studies are not fully consistent. Prenatal exposure to maternal fever and elevated cytokine levels seems to be related to the elevated risk for autism spectrum disorders in the offspring. No replicated findings of an association between prenatal infectious exposure and other mental disorders exist.
CONCLUSIONS: Evidence for the effect of prenatal exposure to maternal infection on risk for mental disorders exists for several different infections, suggesting that common factors occurring in infections (e.g. elevated cytokine levels and fever), rather than the infectious agent itself, might be the underlying factor in increasing the risk for mental disorders. Additionally, it is likely that genetic liability to these disorders operates in conjunction with the exposure. Therefore, genetically sensitive study designs are needed in future studies.