Objective: Interpersonal psychotherapy (IPT) has been proposed for prevention of excess weight gain among adolescents with loss-of-control (LOC) eating. Mixed findings from a trial testing this conjecture warrant elucidation of potential outcome predictors. The therapeutic alliance (adolescent-facilitator emotional bond and task collaboration) may be important for IPT but has received little attention in weight-related interventions. This study evaluated associations of adolescent-reported therapeutic alliance during IPT with weight- and eating-related outcomes.
Methods: Secondary analyses of a randomized controlled trial were conducted to compare group IPT to health education (HE) for preventing excess weight gain among 113 girls (ages 12-17) with body mass index (BMI) at the 75th to 97th percentile and LOC eating. BMI and LOC eating were measured at baseline, 12 weeks (postintervention), and 1 year. Multilevel modeling was used to test associations between change in therapeutic alliance (from session 1 to session 12) and changes in weight- and eating-related outcomes (from postintervention to 1 year). Analyses were controlled for therapeutic alliance after session 1 and for baseline and postintervention outcome values; group assignment (IPT vs. HE) was a moderator.
Results: Increases in emotional bond were associated with decreased weight and with greater decreases in number of LOC eating episodes at 1 year in the IPT group (p<0.05) and with weight gain in the HE group (p<0.05). Greater task collaboration was related to greater weight gain at 1-year follow-up, regardless of group assignment (p<0.05).
Conclusions: The association of therapeutic alliance during IPT with weight and LOC eating outcomes among adolescent girls merits further investigation.
Keywords: Child/adolescent psychiatry; Depressive disorders; Feeding and eating disorders; Interpersonal psychotherapy; Loss of control; Therapeutic alliance.