Perfectionism, anorexia nervosa, and family treatment: How perfectionism changes throughout treatment and predicts outcomes

Abstract Objective This study uses data from a multisite randomized clinical trial to study the role of perfectionism in family‐based treatment (FBT) for adolescent anorexia nervosa (AN). The main aim is to examine the role of baseline perfectionism in treatment response. Method Adolescents ( N = 158; ages 12–18; 89.2% female) and their families were randomized to receive either FBT or systemic family treatment for AN. Eating disorder (ED) pathology, obsessive–compulsive symptoms, and perfectionism were assessed at baseline, end of treatment, and 6‐ and 12‐month follow‐up. Linear regression analyses were used to test whether perfectionism and obsessive–compulsive symptoms at baseline predict ED pathology at all timepoints. An independent samples t test was used to test whether there was a significant difference in the change in perfectionism in either treatment group. Results Baseline maladaptive perfectionism significantly predicted ED pathology but not ideal body weight at all timepoints. The model that included obsessive–compulsive symptoms also predicted ED pathology at all timepoints except 12‐month follow‐up. Perfectionism scores did not change during treatment regardless of treatment type. Discussion Baseline perfectionism predicted treatment response in this study. Interventions might target perfectionism to improve treatment response in AN.