Early response in people with anorexia nervosa receiving cognitive-behavioural therapy for eating disorders (CBT-ED): a latent change study.

Objective

Early improvement predicts good outcome in psychotherapy for eating disorders. Prior studies have examined change in body mass index (BMI) or Eating Disorder Examination Questionnaire scores (EDE-Q) as indicators of early response, but not both simultaneously. Little research has examined early change among Anorexia Nervosa (AN) samples treated with eating disorder-focussed cognitive behavioural therapy (CBT-ED). We studied the process of early change in a fine-grained way to better understand whether early response predicts later response and post-treatment outcomes in CBT-ED for AN, and how the changes in EDE-Q and BMI are related. Method: Adults (N = 193) diagnosed with AN were treated with outpatient CBT-ED. We used bivariate Latent Change Score models to examine change in BMI and EDE-Q and relations between them.

Results

Early change in BMI was independent of early change in EDE-Q. Larger changes in EDE-Q over the first five weeks of therapy followed smaller ones over the next five weeks, meanwhile smaller changes followed larger ones. Early change was predictive of post-treatment scores.

Conclusion

Early change in BMI and EDE-Q during CBT-ED appear to be unrelated and follow different trajectories. Therefore, individuals declared as early responders may differ depending on which variable is used for the decision.