Anorexia nervosa
Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by low weight, food restriction, fear of gaining weight, and an overpowering desire to be thin. Many people with anorexia see themselves as overweight although they are, in fact, underweight. The DSM-5 describe this perceptual symptom like ""disturbance in the way in which one’s body weight or shape is experienced". In research this symptom is called "body image disturbance". Patients with anorexia nervosa also often deny that they have a problem with low weight. They may weigh themselves frequently, eat small amounts, or only eat certain foods. Some exercise excessively, force themselves to vomit (in the "anorexia purging" subtype), or use laxatives to lose weight. Complications may include osteoporosis, infertility, and heart damage, among others. Women will often stop having menstrual periods. In extreme cases, people with anorexia who continually refuse significant dietary intake and weight restoration interventions, and are declared incompetent to make decisions by a psychiatrist, may be fed by force under restraint via nasogastric tube after asking their parents or proxies to make the decision for them.