Motivation to change in adolescents with bulimia nervosa mediates clinical change after treatment.

Several studies have related motivation to change and treatment response in adult patients with bulimia nervosa but there are no longitudinal studies analysing this relationship in adolescents. The objective was to determine whether motivation to change is related to clinical improvement after treatment in adolescent patients with bulimia nervosa. The Bulimia Nervosa Stages of Change Questionnaire, the Eating Disorders Inventory (EDI-2) and the Beck Depression Inventory (BDI) were administered at the beginning of treatment to 40 adolescent patients with bulimia nervosa (DSM-IV) (mean age = 16.2 years). Thirty-one patients were re-assessed after 6 months of treatment. The majority of clinical and psychological variables improved significantly at the second evaluation. There were significant correlations between initial motivation to change and improvement in number of binges and the EDI-2 scales of Bulimia and Interoceptive Awareness. In the stepwise multiple linear regression analysis, which included initial motivation to change and other potential confounding variables such as age, BDI, duration of disorder and body mass index, only motivation to change was selected as a predictor of improvement in number of binges (standardized β coefficient = 0.45; p = 0.012) and of decrease on the Bulimia scale (standardized β coefficient = 0.43; p = 0.029). Regarding improvement in Interoceptive Awareness, only the BDI score was selected as an independent predictor (β coefficient = 0.58; p = 0.002). In conclusion, in adolescent patients receiving treatment for bulimia nervosa, improvement in bulimic symptomatology seems to be especially related to initial motivation to change.