Exposure to Perinatal Infections and Bipolar Disorder: A Systematic Review.

Bipolar disorder (BD) is a debilitating psychiatric disorder and a growing global public health issue. Notwithstanding BD has been conceptualized as a neuroprogressive illness, there are some evidences to suggest a role for neurodevelopmental pathways in the patho-etiology of this disorder. Evidences on the associations between perinatal infections and risk for bipolar disorder have been inconsistent across studies. Here, we performed a systematic review of observational studies on the relationship between exposure to perinatal pathogens and bipolar disorder. A computerized literature search of the PubMed, Embase, and PsyINFO databases till January 31 st , 2015 was performed. Twenty-three studies ultimately met inclusion criteria. Studies investigated exposure to several pathogens namely Cytomegalovirus (CMV), Epstein–Barr Virus (EBV), Herpes simplex virus-1 (HSV-1), Herpes simplex virus-2 (HSV-2), Human herpesvirus 6 (HHV-6), Toxoplasma gondii, Influenza, and Varicella zoster virus (VZV). Overall, studies provided mixed evidences. Thus, contrary to schizophrenia, the role of perinatal infections as risk factors for BD remain inconclusive. Larger studies with a prospective design would be necessary to elucidate the role of previous exposure to infectious agents as a potential risk factor for BD.