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.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, modeling, 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 the 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.