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.
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