IL6 and major depressive disorder: Investigation of the inflammatory cytokines revealed IL1B and IL6 mRNAs were significantly increased in MDD compared to control subjects (IL1B: +87.6%, F(1,59) = 6.052, p = 0.017, controlling for age; IL6: +162.8%, F(1,60) = 4.475, p = 0.039) (Fig. 1E, F).