Abstract
OBJECTIVE: Individually delivered 10-session cognitive-behavioral therapy for nonunderweight eating disorders (CBT-T) has demonstrated comparable levels of effectiveness to longer CBT-ED. Group CBT-T has demonstrated feasibility and potential effectiveness in a pilot study. This study assessed the effectiveness and feasibility of group CBT-T in a larger sample of adults, and evaluated the predictive value of early change on treatment outcomes. METHOD: The data analysis was pre-registered and received ethical clearance, and sample size analysis requirements were met. Using intention to treat analyses (ITT), generalized linear mixed models were used to examine change in eating disorder psychopathology, depression, anxiety, and objective binge eating. Recovery, reliable improvement, and clinically significant change were also examined. Early response as a predictor of treatment outcome was assessed with a paired samples t-test and Pearson's product-moment correlation. RESULTS: Fifty-nine patients started group CBT-T and were entered into the ITT analyses. Twenty-two (37.3%) patients did not complete therapy. Eating disorder psychopathology, depression, anxiety, and objective binge eating significantly reduced from pre- to post-therapy (sustained at 3-month follow-up) with medium to very large effect sizes. Of the treatment completers (n = 37, 62.7%), over 70% recovered on the EDE-Q, and over half showed reliable improvement and clinically significant change. Patients who showed early change in EDE-Q scores by session 4 had significantly greater mean changes in EDE-Q scores from session 1 to session 10. DISCUSSION: The present study shows that group CBT-T can be effective in reducing eating disorder psychopathology and objective binge eating frequency, and improves mood in a transdiagnostic sample of patients with non-underweight eating disorders. Group CBT-T has the potential to increase accessibility to evidence-based treatment for nonunderweight eating disorders.