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Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by a low weight, fear of gaining weight, a strong desire to be thin, and food restriction.〔 Many people with anorexia see themselves as overweight even though they are underweight.〔 If asked they usually deny they have a problem with low weight.〔 Often they weigh themselves frequently, eat only small amounts, and only eat certain foods. Some will exercise excessively, force themselves to vomit, or use laxatives to produce weight loss. Complications may include osteoporosis, infertility and heart damage, among others.〔(【引用サイトリンク】url=http://www.nimh.nih.gov/health/topics/eating-disorders/index.shtml )〕 Women will often stop having menstrual periods.〔 The cause is not known. There appears to be some genetic components with identical twins more often affected than non-identical twins.〔 Cultural factors also appear to play a role with societies that value thinness having higher rates of disease.〔 Additionally, it occurs more commonly among those involved in activities that value thinness such as high level athletics, modelling, and dancing.〔 Anorexia often begins following a major life change or stress inducing event. The diagnosis requires a significantly low weight. The severity of disease is based on body mass index (BMI) in adults with mild disease having a BMI of greater than 17, moderate a BMI of 16 to 17, severe a BMI of 15 to 16, and extreme a BMI less than 15. In children a BMI for age percentile of less than the 5th percentile is often used. Treatment of anorexia involves restoring a healthy weight, treating the 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.〔 A number of types of therapy may be useful including an approach where parents assume responsibility for feeding their child, known as Maudsley family therapy and cognitive behavioral therapy.〔 Sometimes people require admission to hospital to restore weight.〔 Evidence for benefit from nasogastric tube feeding; however, is unclear. Some people will just have a single episode and recover while others may have many episodes over years.〔 Many complications improve or resolve with regaining of weight.〔 Globally anorexia is estimated to affect two million people as of 2013. It is estimated to occur in 0.9% to 4.3% of women and 0.2% to 0.3% of men in Western countries at some point in their life. About 0.4% of young females are affected in a given year and it is estimated to occur ten times less commonly in males.〔〔 Rates in most of the developing world are unclear.〔 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.〔 The term anorexia nervosa was first used in 1873 by William Gull to describe this condition. ==Signs and symptoms== Anorexia nervosa is an eating disorder that is characterized by attempts to lose weight, to the point of starvation. A person with anorexia nervosa may exhibit a number of signs and symptoms, the type and severity of which may vary and may be present but not readily apparent. Anorexia nervosa, and the associated malnutrition that results from self-imposed starvation, can cause complications in every major organ system in the body. Hypokalaemia, a drop in the level of potassium in the blood, is a sign of anorexia nervosa. A significant drop in potassium can cause abnormal heart rhythms, constipation, fatigue, muscle damage and paralysis. Some individuals may lack awareness that they are ill. Symptoms may include: * Refusal to maintain a normal body mass index for one's age * Amenorrhea, a symptom that occurs after prolonged weight loss; causes menses to stop, hair becomes brittle, and skin becomes yellow and unhealthy. * Fearful of even the slightest weight gain and takes all precautionary measures to avoid weight gain and becoming overweight * Obvious, rapid, dramatic weight loss to ''at least'' 15% under normal body weight〔(【引用サイトリンク】url=http://www.anad.org/get-information/get-informationanorexia-nervosa/ )〕 * Lanugo: soft, fine hair growing on the face and body〔 * Obsession with calories and fat content of food * Preoccupation with food, recipes, or cooking; may cook elaborate dinners for others, but not eat the food themselves * Food restriction despite being underweight * Food rituals, such as cutting food into tiny pieces, refusing to eat around others, hiding or discarding food * Purging: May use laxatives, diet pills, ipecac syrup, or water pills; may engage in self-induced vomiting; may run to the bathroom after eating in order to vomit and quickly get rid of ingested calories * Excessive exercise * Perception of self as overweight despite being told by others they are too thin * Intolerance to cold and frequent complaints of being cold; body temperature may lower (hypothermia) in an effort to conserve energy * Hypotension or orthostatic hypotension * Bradycardia or tachycardia * Depression * Solitude: may avoid friends and family; becomes withdrawn and secretive * Abdominal distension * Halitosis (from vomiting or starvation-induced ketosis) * Dry hair and skin, as well as hair thinning * Chronic fatigue〔 * Rapid mood swings 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「anorexia nervosa」の詳細全文を読む スポンサード リンク
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