The Eating Disorder Diagnostic Scale: psychometric features within a clinical population and a cut-off point to differentiate clinical patients from healthy controls.

The Eating Disorder Diagnostic Scale (EDDS) is a brief self-report measure for diagnosing anorexia nervosa, bulimia nervosa and binge eating disorder. Research has provided evidence of the reliability and validity of this scale in non-clinical populations. Our study is the first to examine the psychometric features of the EDDS in a clinical population of eating disordered patients. We identified a cut-off point that differentiates clinical patients from healthy controls. A clinical group of 59 Dutch female eating disordered patients and a control group of 45 Dutch students completed the EDDS, the Eating Disorder Examination Interview, the Body Attitude Test and the Beck Depression Inventory--II. The EDDS showed good test-retest reliability, internal consistency, criterion validity and convergent validity with other scales assessing eating and general pathology. An overall symptom composite cut-off score of 16.5 accurately distinguished clinical patients from healthy controls. The EDDS may be a useful instrument in clinical settings and in aetiologic, prevention and treatment research.