Additional Phenotypes of Eating Disorders: Orthorexia Nervosa

Disordered eating patterns are growing more severe in contemporary society. One such variant to abnormal eating behavior, orthorexia nervosa, reflects a preoccupation with healthy eating, especially quality of food intake, in order to achieve optimum health. Orthorexia nervosa indicates a possible new eating disorder that could be included in the eating disorder classifications in the future. The present chapter aims to provide an up-to-date summary of the state of knowledge on a clinical description of orthorexia nervosa, on proposed diagnostic criteria, on existing similarities and distinctions between orthorexia nervosa and the DSM-5 diagnosis of anorexia nervosa, and on the relationship of orthorexia nervosa with other mental disorders and with psychological disturbances. The chapter also identifies future directions in the field.