Psychoneuroimmunology is defined as the study of the links among behavior, stress, disease, and the immune system.
Psychoneuroimmunology is the study of connections among psychological stress, nervous system functioning, and the immune system; an interdisciplinary field that examines the relationships among behavior, neural, endocrine, and immune processes and interactions among behavioral, neuroendocrine, and immunological processes of adaptation. It is the study of the ways in which experiences, especially stressful ones, alter the immune system and how the immune system in turn influences the central nervous system; a field of study that evolved out of the disciplines of Biology and Psychology and is dedicated to understanding the interplay between these disparate systems. Moreover, Psychoneuroimmunology refers to the study of the effects of stress and other psychological factors on the immune system. It studies the links among behavior, stress, disease, and the immune system.