Psychoneuroimmunology: The interface between behavior, brain, and immunity.

Psychoneuroimmunology is the study of interactions between behavior, the brain, and the immune system. This article is designed to provide an overview of this new field for the general psychologist. The existence of bidirectional communication pathways between the brain and the immune system and the implications of this network for behavior are emphasized. Implications are that behavioral-psychological processes ought to be capable of altering immune function and that events that occur as part of immune responses should modulate behavior. Evidence for influences in both of these directions is reviewed. The discussion of psychological modulation of immunity focuses on classical conditioning and stress, whereas that of immune modification of behavior highlights behavioral effects produced by substances released by the immune system. Finally, the adaptive role that such changes might play is considered.