Our findings suggest that most cases of anorexia nervosa among high school girls are eventually recognized and treated. However, it is worrisome that a large number of girls suffering from early anorexia nervosa and an even greater number suffering from bulimia do not seek treatment for their disorder. In addition, it is clear that girls who do not meet criteria for the full syndromes may nonetheless be engaging in the cardinal behaviors associated with these disorders. Therefore, the pediatrician must actively inquire about weight control practices and binge-purge behavior during the course of routine examinations. These behaviors are sufficiently common that such inquiry should be incorporated into the routine evaluation of every girl, even when there is no obvious reason to be concerned. The vast majority of girls will express dissatisfaction with their weight and report that they have attempted to control their weight in some manner, most often with dieting, in the past year. Normative data from a cross-sectional study such as the one described provide some guidelines as to when such behavior is likely to be associated with other types of problems, such as depressive symptoms or amenorrhea. For example, our data suggest that weight loss of 10 lbs or more in the past year and fasting are more likely to be associated with depressive symptoms and menstrual irregularity than less severe forms of caloric restriction. Our findings also suggest that purging behavior (self-induced vomiting and laxative use), particularly in combination with binge eating, is associated with very high rates of both depressive symptoms and menstrual irregularity.(ABSTRACT TRUNCATED AT 250 WORDS)