Eating disorder subtypes differ in their rates of psychosocial improvement over treatment.

Background: Individuals with Anorexia Nervosa (AN) are renowned for their poor short- and long-term treatment outcomes. To gain more insight into the reasons for these poor outcomes, the present study compared patients with AN-R (restrictive subtype), AN-BP (binge-purge subtype), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS) over 12 weeks of specialized eating disorders treatment. Eighty-nine patients completed the Eating Disorder Examination- Questionnaire (EDE-Q) and various measures of psychosocial functioning at baseline, and again after weeks 3, 6, 9, and 12 of treatment.

Results: Multilevel modeling revealed that, over the 12 weeks, patients with AN-BP and AN-R had slower improvements in global eating disorder pathology, shape concerns, and self-compassion than those with EDNOS and BN. Patients with AN-BP had slower improvements in shame, social safeness (i.e., feelings of warmth in one's relationships), and received social support compared to those with AN-R, BN, and EDNOS.

Conclusions: These findings support the need for more effective and comprehensive clinical interventions for patients with AN and especially AN-BP. Results also highlight not-yet studied processes that might contribute to the poor outcomes AN patients often face during and after treatment.