In addition to inflammatory cytokines, it has been claimed that the main antiviral cytokines, the type I IFNs (consisting of IFNalpha and IFN-beta) induced in the course of viral infections by activation of innate immune receptors or given as drug treatment may also lead to sickness behaviour and depression with significant impact on the well-being of the patient and the feasibility of the treatment (Smith et al., 2015). This evidence concerns the gene IFNA1 and major depressive disorder.