Sometimes, especially in more advanced stages of the condition, periods of almost complete starvation are punctuated by bouts of excessive eating. This disgusts the girl who gets rid of the food by making herself vomit. She then realizes that vomiting and purging are effective ways of combating her episodes of 'bingeing' and these may become established practices. In time, if the condition is not recognized and treated, severe weight loss is achieved - sometimes as much as fifty per cent of normal weight. Apart from the obvious thinness, a characteristic feature is the resultant effect on sexual function.
Menstruation ceases or, in the case of a boy, there is loss of sexual drive and impotence.
In a child that has not yet reached puberty sexual development is delayed and menstrual periods do not start. Apart from the physical consequences, anorexia nervosa may cause severe anxiety or depression. A girl may become so irritable and tense that serious conflicts within her family and among her friends may arise. There is some disagreement about the answer perhaps because it is not a very common, condition and therefore few doctors have treated sufficient numbers of patients to gain a full understanding of it. It seems that the most likely explanation is that the girl has a basic fear of growing up.