Anorexia nervosa

Anorexia nervosa (AN), 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. Individuals with anorexia nervosa have a fear of being overweight or being seen as such, although they are in fact underweight. The DSM-5 describes this perceptual symptom as "disturbance in the way in which one's body weight or shape is experienced". In research and clinical settings, this symptom is called "body image disturbance". Individuals with anorexia nervosa also often deny that they have a problem with low weight. They may weigh themselves frequently, eat small amounts, and only eat certain foods. Some exercise excessively, force themselves to vomit (in the "anorexia purging" subtype), or use laxatives to lose weight and control body shapes, and/or binge eat. Medical complications may include osteoporosis, infertility, and heart damage, along with the cessation of menstrual periods. In extreme cases, patients with anorexia nervosa 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. The cause of anorexia is currently unknown. There appear to be some genetic components with identical twins more often affected than fraternal twins. Cultural factors also appear to play a role, with societies that value thinness having higher rates of the disease. Additionally, it occurs more commonly among those involved in activities that value thinness, such as high-level athletics, modeling, and dancing. Anorexia often begins following a major life-change or stress-inducing event. Treatment of anorexia involves restoring the patient back to a healthy weight, treating their underlying psychological problems, and addressing behaviors that promote the problem.