TNF and bipolar disorder: In almost half the cases with schizophrenia and one-third of cases with bipolar disorder, a 200% to 700% increase in messenger RNAs (mRNAs) encoding proinflammatory cytokines such as interleukin (IL) 1β, IL-8, IL-6, and tumor necrosis factor (TNF) have been found in the blood (3, 4, 5), subependymal zone (6), prefrontal cortex (PFC) (7,8), and midbrain (9,10).