Clinical features and physiological response to a test meal in purging disorder and bulimia nervosa.

CONTEXT Recent data suggest that purging disorder, a recently characterized form of eating disorder not otherwise specified, may be worthy of specific delineation in nosological schemes. However, more data are needed to determine how purging disorder differs from bulimia nervosa. OBJECTIVE To examine clinical features and subjective as well as objective physiological responses to a standardized test meal in purging disorder compared with bulimia nervosa and controls. DESIGN Study visit 1 included psychological assessments with structured clinical interviews and questionnaires. Study visit 2 included assessment of test-meal responses. SETTING Participants recruited from the community completed test-meal studies in a General Clinical Research Center. PARTICIPANTS Women with DSM-IV bulimia nervosa-purging subtype (n = 37) and purging disorder (n = 20) and non-eating disorder controls (n = 33) with a body mass index (calculated as weight in kilograms divided by height in meters squared) between 18.5 and 26.5 who were free of psychotropic medications. MAIN OUTCOME MEASURES Assessments of eating disorder severity, postprandial cholecystokinin response, and subjective responses to test meals. RESULTS Eating abnormalities were significantly elevated in participants with purging disorder and bulimia nervosa compared with controls but did not differ between eating disorder groups. Participants with purging disorder demonstrated significantly greater postprandial cholecystokinin release compared with participants with bulimia nervosa (t(76.44) = 2.51; P = .01) and did not differ significantly from controls (t(75.93) = 0.03; P = .98). Participants with purging disorder reported significantly greater postprandial fullness and gastrointestinal distress compared with participants with bulimia nervosa and controls. CONCLUSIONS Purging disorder is a clinically significant disorder of eating that appears to be distinct from bulimia nervosa on subjective and physiological responses to a test meal. Findings support further consideration of purging disorder for inclusion in the classification of eating disorders. Future studies on the psychobiology of purging disorder are needed to understand the propensity to purge in the absence of binge eating.