Some recent observations on the pathogenesis of anorexia nervosa.

Studies of diagnostic subtypes within the anorexia nervosa syndrome has given rise to the differentiation of a bulimic subgroup as distinct from the restrictive type of anorexia nervosa. The bulimic subtype is characterized by the use of vomiting and laxatives to induce weight loss; a display of impulse-related behaviours; extraversion and sexual activity in contrast to the isolation of the restrictive group; and a family history of obesity in the mother, all suggesting a subcategory within the primary anorexia nervosa syndrome. Investigation of behaviours and attitudes related to anorexia nervosa in a group of dancers disclosed a significantly elevated attitude toward food and body image characteristic of anorexia nervosa in this group and ten times the expected prevalence of the disorder itself. This is suggestive of the relative importance of cultural pressures towards thinness and anorexia nervosa in certain populations as one factor amongst others in the multi-determined origin of this condition. This cultural pressure is consistent with a disturbance of body image perception in anorexia nervosa. This disturbance seems to be stable in the same individual over a period of one year, is related to a poor prognosis and is correlated with measures of psychopathology including helplessness, depression and anhedonia. It is also correlated with a satiety defect as reflected in a failure to develop an aversion to sucrose when directly tested.