Depression's double hit: immune dysfunction and viral reactivation

Cytomegalovirus (CMV), a common herpesvirus that establishes enduring latent infections, is increasingly recognized as a potential pathological co-factor in diverse medical disorders that are characterized by immunosuppression and/or inflammation. Inflammation and immunosuppression can occur in clinical depression, possibly explaining reported associations between CMV and depression. This paper will evaluate the evidence for the hypothesis that depressed individuals are more susceptible to CMV infection and reactivation, which in turn contributes to the origin, worsening or maintenance of depressive symptoms.This article is part of the discussion meeting issue 'The indirect effects of cytomegalovirus infection: mechanisms and consequences'.