Nutrition, serotonin and behavior in anorexia and bulimia nervosa.

Anorexia nervosa (AN) and bulimia nervosa (BN) are disorders characterized by aberrant patterns of feeding behavior and weight regulation, and disturbances in attitudes toward weight and shape and the perception of body shape. In AN, there is an inexplicable fear of weight gain and unrelenting obsession with fatness even in the face of increasing cachexia. BN usually emerges after a period of dieting, which may or may not have been associated with weight loss. Binge eating is followed either by self-induced vomiting or some other means of compensation for the excess of food ingested. The majority of people with BN have irregular feeding patterns and satiety may be impaired. Although abnormally low body weight is an exclusion for the diagnosis of BN, some 25–30% of patients with BN who present to treatment centers have a prior history of AN; however, all individuals with BN have pathological concern with weight and shape. Common to individuals with AN or BN are low self-esteem, depression, and anxiety. In certain respects, both diagnostic labels are misleading. Individuals affected with AN rarely have complete suppression of appetite, but rather exhibit a volitional, and, more often than not, ego syntonic resistance to feeding drives while eventually becoming preoccupied with food and eating rituals to the point of obsession. Similarly, BN may not be associated with a primary, pathological drive to overeat; rather, like individuals with AN, those