The Neuroimmune System in Psychiatric Disorders

The earliest evidence for neuroimmune interaction and regulation is the classical immune conditioning experiment of Ader and Cohen in 1975 (Ader, 1987). Since then, it is well established that the central nervous system (CNS) and the immune system interact and regulate one another’s function (Blalock, 1989; Madden and Felten, 1995). This interaction can be particularly important at times of extraordinary stress, whether due to psychological factors or to a physical response to an injury or an infection. The CNS regulates immune system function with classical neurotransmitters acting through the central nervous system and peripherally through the sympathetic nervous system; and with neuropeptides also acting through both the central and peripheral nervous systems. The immune system, in turn, alters CNS function, particularly through the release of cytokines. While this reciprocal regulation between the CNS and the immune system is designed to maintain homeostasis, dysfunction in one can lead to aberrant function in the other, producing a pathological state.