Anorexia Nervosa is a chronic eating disorder. It is an illness which mainly affects adolescent girls, although it can occur in both sexes at any age. The most common feature is weight loss coupled with a change in behaviour. Other symptoms include a distorted body image, obsessive exercise and a desperate fear of gaining weight. Many anorexics ignore their hunger and so control their need to eat. Starvation and weight loss can lead to serious medical problems.