IL6 and major depressive disorder: An important genome-wide pharmacogenetic study, in a large sample of MDD patients treated with antidepressants, found that the major alleles of SNP rs1126757 in the gene encoding IL-11 and of SNP rs7801617 in the IL-6 gene (C and G, respectively) predicted a worse antidepressant response (Uher et al, 2010).