Objective: This study sought to characterize a large number of adult outpatients diagnosed with eating disorder not otherwise specified (EDNOS).

Methods: The sample consisted of 1,449 patients who were classified as anorexia nervosa (AN), bulimia nervosa (BN), or assigned to one of six EDNOS categories. Eating disorder groups were compared on demographic features, symptom frequencies, and psychological functioning.

Results: Forty percent of the sample was categorized as EDNOS. A subgroup of purging only patients closely resembled the BN purging subtype. Although EDNOS subthreshold BN patients reported less psychopathology than full syndrome BN they, nevertheless, displayed clinical levels of disturbance. Patients who binge-eat once a week demonstrate a profile of psychological functioning similar to those who binge eat twice a week.

Conclusions: Consistent with previous research, in this sample there were subgroups embedded in the EDNOS category that both share similarities with and differ from full syndrome BN.