The measurement of impairment due to eating disorder psychopathology.

Eating disorders have a profound and highly specific impact on psychosocial functioning. The aim of this research was to develop a measure of such secondary impairment. A 16-item, self-report instrument was developed, the Clinical Impairment Assessment (CIA), which was designed to measure such impairment overall and in three specific domains (personal, cognitive, social). The psychometric properties of the instrument were evaluated using data collected in the context of a transdiagnostic treatment trial. The findings consistently supported the utility of the instrument with the CIA being shown to have high levels of internal consistency, construct and discriminant validity, test-retest reliability, and sensitivity to change. The CIA should be of value to clinicians when assessing patients with eating disorders and their response to treatment. It should also help inform epidemiological research