Development, psychometric properties and preliminary clinical validation of a brief, session-by-session measure of eating disorder cognitions and behaviors: The ED-15.

OBJECTIVE: In the treatment research literature on other psychological disorders, there is a move towards session-by-session symptom measurement. The necessary measures need to be brief, focused on core features since the last session, and readily available to clinicians. There is no measure in the eating disorders that meets those criteria. This research reports the development and validation of such a self-report questionnaire.

METHOD: The authors generated and refined a brief set of attitudinal and behavioral items. The resulting questionnaire (the ED-15) and an existing measure (Eating Disorders Examination-Questionnaire; EDE-Q) were completed by a large nonclinical adult sample (N = 531), a group of self-reported eating disorder sufferers (N = 63), and a group of women (N = 33) diagnosed with bulimia nervosa or atypical bulimia nervosa and undertaking cognitive-behavioral therapy.

RESULTS: Factor analysis identified two scales (Weight and Shape Concerns; Eating Concerns), with strong internal consistency and test-retest reliability. Correlations with the EDE-Q (r = 0.889) indicates that the ED-15 and EDE-Q measure near-identical constructs. The ED-15 differentiated self-reported eating-disordered and nonclinical groups to the same degree as the longer EDE-Q. Session-by-session analysis of the CBT treatment group demonstrated that the different ED-15 scales changed in different patterns across therapy.

DISCUSSION: The ED-15 is not proposed as an alternative to existing measures, but as a complementary tool, used to measure session-by-session change for clinical and research purposes. Future research will track changes in ED-15 scores across therapy, to determine the importance of very early response to therapy and sudden changes.