IL6 and schizophrenia: Although both human and animal studies show that chronic stress increases inflammatory cytokines in the blood and the brain,87 it is also apparent that cytokines such as IL1 and IL6 can act as potent activators of the HPA axis.88, 90, 91 Thus, although chronic stress may be contributing to the activated immune/inflammation module in the CP of schizophrenia it is likely part of a complex interaction.