MODEL RELEASED. Anorexic woman (left) being counselled as she eats a meal at a clinic. Anorexia nervosa is a psychological disorder in which sufferers have a distorted sense of their own body, typically feeling that they are overweight despite being severely underweight. It causes massive weight loss, often to potentially fatal levels. Hospital treatment is often required to make the patient gain weight, and psychotherapy may be needed to help the patient recover normal eating habits again. It is most common amongst young women.