Although alterations in peripheral cytokines such as IL-6 do not necessarily fully represent the state of central immune response, elevated levels of IL-6 have been found to be present in acute phase of multiple psychiatric disorders, including schizophrenia, bipolar disorder, and major depressive disorder, and have even been suggested to be a possible state marker for schizophrenia36, this suggests a common immune stress-related phenomenon in acute phase of schizophrenia or even other psychiatric disorders37. This evidence concerns the gene IL6 and bipolar disorder.