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Open Access Highly Accessed Research article

Cognitive behaviour therapy response and dropout rate across purging and nonpurging bulimia nervosa and binge eating disorder: DSM-5 implications

Zaida Agüera12, Nadine Riesco2, Susana Jiménez-Murcia123, Mohammed Anisul Islam12, Roser Granero14, Enrique Vicente2, Eva Peñas-Lledó5, Jon Arcelus6, Isabel Sánchez2, Jose Manuel Menchon237 and Fernando Fernández-Aranda123*

Author Affiliations

1 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto Salud Carlos III, Madrid, Spain

2 Department of Psychiatry, University Hospital of Bellvitge-IDIBELL, Barcelona, Spain

3 Department of Clinical Sciences, School of Medicine, University of Barcelona, Barcelona, Spain

4 Departament de Psicobiologia i Metodologia, Universitat Autònoma de Barcelona, Barcelona, Spain

5 CICAB Clinical Research Centre, Extremadura University Hospital and Medical School, Badajoz, Spain

6 Leicester Eating Disorder Service, Brandon Mental Health Unit, Leicester General Hospital, Leicester, UK

7 CIBER Salud Mental (CIBERSAM), Instituto Salud Carlos III, Barcelona, Spain

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BMC Psychiatry 2013, 13:285  doi:10.1186/1471-244X-13-285

Published: 7 November 2013



With the imminent publication of the new edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), there has been a growing interest in the study of the boundaries across the three bulimic spectrum syndromes [bulimia nervosa-purging type (BN-P), bulimia nervosa-non purging type (BN-NP) and binge eating disorder (BED)]. Therefore, the aims of this study were to determine differences in treatment response and dropout rates following Cognitive Behavioural Therapy (CBT) across the three bulimic-spectrum syndromes.


The sample comprised of 454 females (87 BED, 327 BN-P and 40 BN-NP) diagnosed according to DSM-IV-TR criteria who were treated with 22 weekly outpatient sessions of group CBT therapy. Patients were assessed before and after treatment using a food and binging/purging diary and some clinical questionnaires in the field of ED. “Full remission” was defined as total absence of binging and purging (laxatives and/or vomiting) behaviors and psychological improvement for at least 4 (consecutive).


Full remission rate was found to be significantly higher in BED (69.5%) than in both BN-P (p < 0.005) and BN-NP (p < 0.001), which presented no significant differences between them (30.9% and 35.5%). The rate of dropout from group CBT was also higher in BED (33.7%) than in BN-P (p < 0.001) and BN-NP (p < 0.05), which were similar (15.4% and 12.8%, respectively).


Results suggest that purging and non-purging BN have similar treatment response and dropping out rates, whereas BED appears as a separate diagnosis with better outcome for those who complete treatment. The results support the proposed new DSM-5 classification

Binge eating disorder (BED); Bulimia nervosa (BN); Cognitive-behavioural therapy (CBT); Classification; DSM-5