Eating Disorder Not Otherwise Specified in an Inpatient Unit: The Impact of Altering the DSM-IV Criteria for Anorexia and Bulimia Nervosa Riccardo Dalle Grave * and Simona Calugi Department of Eating and Weight Disorder, Villa Garda Hospital, Garda (VR), Italy Objective: To evaluate (1) the Eating Disorder Not Otherwise Specified (EDNOS) prevalence in an eating disorder inpatient unit; (2) the impact of altering the diagnostic criteria for anorexia nervosa and bulimia nervosa on the prevalence of EDNOS. Method: One hundred and eighty six eating disorder patients consecutively hospitalised were included in the study. The preva- lence of anorexia nervosa, bulimia nervosa and EDNOS was eval- uated with the Eating Disorder Examination (EDE). The EDNOS prevalence was recalculated after the alteration of three diagnostic criteria for anorexia nervosa and one for bulimia nervosa. Results: Seventy eight patients (41.9%) met the diagnostic criteria for anorexia nervosa, 33 (17.8%) for bulimia nervosa and 75 (40.3%) for EDNOS. The alteration of the DSM-IV diagnostic criteria reduced the prevalence of EDNOS to 28 cases (15%). Conclusion: EDNOS is a very frequent diagnostic category in an inpatient setting. Altering the diagnostic criteria for anorexia ner- vosa and bulimia nervosa reduced significantly the prevalence of EDNOS. Copyright # 2007 John Wiley & Sons, Ltd and Eating Disorders Association. Keywords: DSM-IV; NOS; eating disorder; diagnosis; classification; anorexia nervosa; bulimia nervosa INTRODUCTION The DSM-IV classification of eating disorders in- cludes anorexia nervosa, bulimia nervosa and EDNOS (American Psychiatric Association, 1994). Eating Disorder Not Otherwise Specified (EDNOS) is a diagnostic category reserved for individuals suffering from an eating disorder of clinical severity that does not meet the diagnostic criteria for anorexia nervosa or bulimia nervosa. The diagnosis of EDNOS, as the other NOS category in DSM-IV (American Psychiatric Associ- ation, 1994), was intended to indicate a category within a class of disorders that is residual to the specific categories in that class (American Psychia- tric Association, 1980). Nevertheless, recent studies have found that EDNOS is the most common eating disorder diagnosis made in outpatient settings, with European Eating Disorders Review Eur. Eat. Disorders Rev. 15, 340–349 (2007) * Correspondence to: Riccardo Dalle Grave, MD, Department of Eating Disorder and Weight Disorder, Villa Garda Hospital, Via Montebaldo 89, 37016 GARDA (VR), Italy. Tel: þ39-045-8103915. Fax: þ39-051-6364502. E-mail: rdalleg@tin.it Copyright # 2007 John Wiley & Sons, Ltd and Eating Disorders Association. Published online 26 July 2007 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/erv.805