The development of a scale to measure cognitive distortions in bulimia

The Bulimia Cognitive Distortions Scale (BCDS) was developed to measure irrational beliefs and cognitive distortions associated with bulimia. The final 25-item scale was found to have excellent internal consistency with high item to total correlations and a coefficient alpha of .97. Factor analysis revealed two clear factors measuring cognitive distortions related to automatic eating behaviors and to physical appearance. Data attesting to the convergent and divergent validity of the BCDS are also presented. With 110 subjects (55 bulimics, 55 controls), a discriminant analysis revealed the BCDS to be the only significant variable in predicting group membership, correctly classifying 93.6% of all subjects. The BCDS was also predictive of severity of bulimia as measured by the frequency of binge eating episodes. The potential of the BCDS as both a diagnostic and research instrument is discussed.