Predictors of early response in conjoint and separated models of family-based treatment for adolescent anorexia nervosa.

OBJECTIVE: Early response, as indicated by early weight gain, in family-based treatment (FBT) for adolescent anorexia nervosa (AN) predicts remission at end of treatment. However, little is known about what factors contribute to early response. Further, no previous studies have examined early response to separated forms of FBT.

METHOD: Data from a randomised clinical trial of conjoint FBT and separated FBT (parent-focused treatment, PFT) were analysed to examine the timing and amount of early weight gain that predicted remission and identify factors associated with early response.

RESULTS: Weight gain of at least 2.80 kg in FBT (N = 55) and 2.28 kg in PFT (N = 51), by Session 5, were the best predictors of remission at end of treatment. Early response in FBT was predicted by greater paternal therapeutic alliance and lower paternal criticism. Early response in PFT was predicted by less severe eating-disorder symptoms and negative affect at baseline, lower maternal criticism, and greater adolescent therapeutic alliance.

CONCLUSIONS: The results confirm that early weight gain is an important prognostic indicator in both conjoint FBT and PFT and suggest that addressing negative emotion, parental criticism, and therapeutic alliance early in treatment could improve remission rates.