Development and evaluation of a treatment fidelity instrument for family-based treatment of adolescent anorexia nervosa

Abstract

This study provides data on the psychometric properties of a newly developed measure of treatment fidelity in Family-Based Treatment (FBT) for adolescent anorexia nervosa (AN). The Family Therapy Fidelity and Adherence Check (FBT-FACT) was created to evaluate therapist adherence and competency on the core interventions in FBT. Participants were 45 adolescents and their families sampled from three randomized clinical trials evaluating treatment for AN. Trained fidelity raters evaluated 19 therapists across 90 early session recordings using the FBT-FACT. They also rated an additional 15 session 1 recordings of an alternate form of family therapy-Systemic Family Therapy for the purpose of evaluating discriminant validity of the FBT-FACT. The process of development and the psychometric properties of the FBT-FACT are presented. Overall fidelity ratings for each session demonstrated moderate to strong inter-rater agreement. Internal consistency of the measure was strong for sessions 1 and 2 and poor for session 3. Principal components analysis suggests sessions 1 and 2 are distinct interventions. The FBT-FACT demonstrates good reliability and validity as a measure of treatment fidelity in the early phase of FBT.