IL6 and schizophrenia: Peripheral IL-6 may enter the CNS through the choroid plexus, or through a subtle disturbance in the integrity of the blood–brain barrier.57 Irrespective of the origin of production, pathologic increase in CNS IL-6 may have detrimental, neuromodulatory effects on the hypothalamic–pituitary–adrenal axis58 and a mechanistic role in cognitive deficits seen in schizophrenia.59, 60 CNS IL-6 has been proposed as an important mediator of altered synaptic connectivity, brain structure and function in schizophrenia, implicating this cytokine as a potential target for immunotherapy.9