Restless activation and drive for activity in anorexia nervosa may reflect a disorder of energy homeostasis.

Abstract

Anorexia nervosa (AN), an uncommon disorder of voluntary food restriction emerging during adolescence, is a condition known in Western Europe for at least 500 years, if not longer. Although AN is currently categorized as an eating disorder, “anorexia” or “loss of appetite” are infrequent. AN is also an intensely personal disorder in that the person with AN concentrates most of his/her thoughts, emotions, and actions on food avoidance and weight loss. The etiology of AN remains obscure. There is good agreement that AN constitutes a clinical entity and that it does not develop in the context of another psychiatric disorder. Nevertheless, co‐morbid psychiatric disorders are frequently associated with AN and they have an impact on the severity and duration of AN. Importantly, twin and family studies point to a significant genetic component in AN with twin‐based heritability estimates ranging from 50 to 80%.1 So far, neither genome‐wide linkage studies or candidate gene studies, nor genome‐wide association studies (GWAS) have reported incontrovertible findings.1 The occurrence of AN in other cultures has renewed the interest in taking a fresh look at the clinical phenomenology of AN. Indeed, research aimed at identifying and refining new phenotypes might provide a link to genetic studies and open avenues for exploring and understanding the pathology of the disorder.