APA Dictionary of Psychology

a disruption in the body’s physical and chemical processing of food into energy (see metabolism), caused when one or more organs (e.g., liver, pancreas) do not function properly. Metabolic disorders may be congenital (e.g., cystic fibrosis, sickle-cell anemia, Tay–Sachs disease) or acquired (e.g., some cases of nonalcoholic fatty liver disease).