IFNA1 and major depressive disorder: IFN-α has been demonstrated to have regulatory effects on the neuronal excitabilities in CNS (Calvet and Gresser, 1979) and influence the function of neurotransmitter metabolism and neuroendocrine linking to depression (Menzies et al., 1996; Kumai et al., 2000; Kitagami et al., 2003; De La Garza et al., 2005; Felger et al., 2007).