“Stress is defined as a state of real or perceived threat to homeostasis. The principal effectors of the stress system are corticotropin-releasing hormone (CRH), arginine vasopressin, the proopiomelanocortin-derived peptides α-melanocyte–stimulating hormone and β-endorphin, the glucocorticoids, and the catecholamines norepinephrine and epinephrine.
Appropriate responsiveness of the stress system to stressors is a crucial prerequisite for a sense of well-being, adequate performance of tasks, and positive social interactions. By contrast, inappropriate responsiveness of the stress system may impair growth and development and may account for various endocrine, metabolic, autoimmune, and psychiatric disorders. The development and severity of these conditions primarily depend on the genetic vulnerability of the individual, the exposure to adverse environmental factors, and the timing of stressful event(s). Prenatal life, infancy, childhood, and adolescence are critical periods characterized by increased vulnerability to stressors.”