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Etiology of anorexia nervosa
1. The etiology of anorexia nervosa is unknown but appears to involve a combination of psychological, biologic, and cultural risk factors. Risk factors, such as sexual or physical abuse and a family history of mood disturbance, are best viewed as nonspecific risk factors that increase vulnerability to a range of psychiatric disorders, including anorexia nervosa.
2. Patients who develop anorexia nervosa are inclined to be more obsessional and perfectionist than their peers. The disorder often begins as a diet not distinguishable at the outset from those undertaken by many adolescents and young women. As weight loss progresses, the fear of gaining weight grows; dieting becomes stricter; and psychological, behavioral, and medical aberrations increase.
3. Numerous physiologic disturbances, including abnormalities in a variety of neurotransmitter systems, have been described in anorexia nervosa. It is difficult to distinguish neurochemical, metabolic, and hormonal changes that may have a role in the initiation or perpetuation of the syndrome from those that are secondary to the disorder.
4. Genetic factors contribute to the risk of development of anorexia nervosa, as its incidence is greater in families with one affected member and the concordance in monozygotic twins is greater than in dizygotic twins. However, specific genes have not been identified.
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