A teenage girl with low body mass index due to restricting food intake

Anorexia nervosa (AN) is an eating disorder that is characterized by restriction of energy intake leading to significantly low body weight, an intense fear of gaining weight or persistent behavior that interferes with weight gain, and disturbance in the way one’s body weight or shape is experienced. Because many patients with AN attempt to conceal their efforts to lose weight and minimize their symptoms, obtaining information from a caregiver is an important part of the assessment. A medical history and physical examination must be completed to assess medical stability, including review of vital signs, electrocardiogram, and laboratory studies. Medically unstable patients require a medical admission for refeeding and stabilization, including monitoring for refeeding syndrome. Pharmacotherapy should not be used as the primary treatment for patients with AN. The most evidence-based psychotherapy approach for children and adolescents is family-based treatment (Maudsley family therapy).