Anorexia nervosa, often referred to simply as anorexia, is an eating disorder characterized by low weight, fear of gaining weight, and a strong desire to be thin, resulting in food restriction. Many people with anorexia see themselves as overweight even though they are in fact 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.Women will often stop having menstrual periods.
The cause is not known. There appear 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 2.9 million people as of 2015. 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 women are affected in a given year and it is estimated to occur ten times less commonly in men. 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, a nearly 6 times increased risk. The term anorexia nervosa was first used in 1873 by William Gull to describe this condition.
A diagnostic assessment includes the person’s current circumstances, biographical history, current symptoms, and family history. The assessment also includes a mental state examination, which is an assessment of the person’s current mood and thought content, focusing on views on weight and patterns of eating.
Anorexia nervosa is classified under the Feeding and Eating Disorders in the latest revision of the Diagnostic and Statistical Manual of Mental Disorders (DSM 5).
Relative to the previous version of the DSM (DSM-IV-TR), the 2013 revision (DSM5) reflects changes in the criteria for anorexia nervosa, most notably that of the amenorrhea criterion being removed. Amenorrhea was removed for several reasons: it does not apply to males, it is not applicable for females before or after the age of menstruation or taking birth control pills, and some women who meet the other criteria for AN still report some menstrual activity.
There are two subtypes of AN:
- Binge-eating/purging type: the individual utilizes binge eating or displays purging behavior as a means for losing weight. It is different from bulimia nervosa in terms of the individual’s weight. An individual with binge-eating/purging type anorexia can maintain a healthy or normal weight, but is usually significantly underweight. People with bulimia nervosa on the other hand can sometimes be overweight.
- Restricting type: the individual uses restricting food intake, fasting, diet pills, or exercise as a means for losing weight; they may exercise excessively to keep off weight or prevent weight gain, and some individuals eat only enough to stay alive.
Levels of severity
Body mass index (BMI) is used by the DSM-5 as an indicator of the level of severity of anorexia nervosa. The DSM-5 states these as follows:
- Mild: BMI of greater than 17
- Moderate: BMI of 16–16.99
- Severe: BMI of 15–15.99
- Extreme: BMI of less than 15
Content retrieved from: https://en.wikipedia.org/wiki/Anorexia_nervosa.