Anorexia nervosa
Anorexia nervosa (AN), often referred to simply as anorexia, is an eating disorder characterized by food restriction, body image disturbance, 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, despite the fact that they are typically 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 causes of anorexia are varied and may differ from individual to individual. There is emerging evidence that there is a genetic component, 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. While medications do not help with weight gain, they may be used to help with associated anxiety or depression. Different therapy methods may be useful, such as cognitive behavioral therapy or an approach where parents assume responsibility for feeding their child, known as Maudsley family therapy. Sometimes people require admission to a hospital to restore weight. Evidence for benefit from nasogastric tube feeding is unclear; such an intervention may be highly distressing for both anorexia patients and healthcare staff when administered against the patient's will under restraint. Some people with anorexia will have a single episode and recover while others may have recurring episodes over years. Many complications improve or resolve with the regaining of weight.It is estimated to occur in 0.3% to 4.3% of women and 0.2% to 1% of men in Western countries at some point in their life. About 0.4% of young women are affected in a given year and it is estimated to occur ten times more commonly among women than men. Often it begins during the teen years or young adulthood. While anorexia became more commonly diagnosed during the 20th century, it is unclear if this was due to an increase in its frequency or simply better diagnosis. In 2013, it directly resulted in about 600 deaths globally, up from 400 deaths in 1990. Eating disorders also increase a person's risk of death from a wide range of other causes, including suicide. About 5% of people with anorexia die from complications over a ten-year period.
