Paper in International Journal of Eating Disorders
- Maguire, S., Touyz, S., Surgenor, L., Crosby, R.D., Engel, S.G., Lacey, H., Heywood-Everett, S., Le Grange, D. (2011). The clinician administered staging instrument for anorexia nervosa: Development and psychometric properties. International Journal of Eating Disorders, DOI: 10.1002/eat.20951.
Objective: To develop and evaluate an instrument to assess severity in anorexia nervosa (AN), the Clinician Administered Staging Instrument for Anorexia Nervosa (CASIAN).
Method: Candidate items for the CASIAN were developed in three phases (domain, content, and item generation) followed by a pilot study. The psychometric properties of the resultant 34-item questionnaire were investigated in cross-sectional and longitudinal samples (N = 171) with DSM-IV AN and subthreshold AN.
Results: Item and factor analysis procedures resulted in a refined 23-item CASIAN comprising of six factors ("Motivation," "Weight," "Illness Duration," "Obsessionality," "Bulimic Behaviors," and "Acute Issues"). The CASIAN had high internal consistency (.811), test-retest (.957), and interrater reliability (.973). Preliminary support for the convergent, discriminant, concurrent, and predictive validity of the CASIAN was found.
Discussion: The CASIAN is a psychometrically sound instrument. Further studies are needed to confirm the factor structure and assess its clinical and research utility.