Interestingly, when stratified by IL6 C-174G polymorphism, higher baseline depressive symptom severity measured by MADRS and BDI predicted higher risk of depression in the course of antiviral treatment only in high IL-6 producers—G allele carriers (patients with GG and CG genotypes) (p = 0.004, p = 0.00008, respectively). Here, IL6 is linked to major depressive disorder.