Language style matching and treatment outcome in anorexia nervosa

Objective Psychotherapy is the treatment of choice for anorexia nervosa (AN) but mechanisms of action are still largely unknown. Growing research suggests that synchrony between patient and therapist contributes to treatment success. Adding to this literature, this study examined the association between language style matching (LSM) among patient and therapist as an indicator of interpersonal (verbal) synchrony and treatment outcome in AN. Method Audio recordings of mid-treatment therapy sessions (n = 25) in a multi-centre randomized controlled trial on the Maudsley Model of Anorexia Nervosa Treatment for Adults were transcribed and used to calculate LSM for each patient-therapist dyad. These scores were used to predict treatment outcome at 12-month follow-up. Results LSM did not predict body mass index (primary outcome) at follow-up. However, higher LSM (M = 0.87, SD = 0.04) was associated with lower eating disorder psychopathology (accounting for 11% of the variance) and higher recovery rates (accounting for 28% of variance) at follow-up. Conclusions These preliminary findings suggest that verbal synchrony between patients with AN and their therapists contributes to favourable treatment outcomes. High levels of LSM may reflect therapeutic empathy, cooperation, or mutual positive perception. Further research should explore the mechanisms of linguistic synchrony with larger samples to allow for stronger conclusions.