Indeed, accumulating evidence showed an increase in proinflammatory mediators, principally IL-6, IL-1β, interferon-γ (IFN-γ), and TNF-α in depressed individuals and in patients developing depressive symptoms after therapeutic treatments, such as IFN-α therapy for chronic hepatitis C [53,54,55,56,57]. Here, IFNG is linked to chronic hepatitis C virus infection.