Psychoneuroimmunoendocrinology is the study of the interaction between the psyche, neural function, endocrine function and immune responses. These systems can interact through two pathways: changes in neural and endocrine functions that alter immune responses or stimulation of immune responses that modify the functionality of the endocrine system and the CNS. Behavioral processes are able to initiate both pathways, which leads to altered behavior in an individual . Interactions between these various systems regulate a variety of physiological processes, and their normal interaction helps to reduce the vulnerability of individuals to certain diseases [2, 3]. One aim of psychoneuroimmunoendocrinology is to apply medical knowledge to different psychological disorders (e.g., depression), neurological conditions (e.g., dementia), immune disorders (e.g., autoimmune diseases) and neoplastic diseases .