ORIGINAL ARTICLE A randomized controlled trial of group cognitive remediation therapy for anorexia nervosa: Effects on set-shifting tasks for inpatient adults and adolescents Laura E. Sproch PhD 1 | Kimberly P. Anderson PhD 1 | Martin F. Sherman PhD 2 | Steven F. Crawford MD 3 | Harry A. Brandt MD 3 1 Department of Psychology, The Center for Eating Disorders at Sheppard Pratt, Baltimore, Maryland 2 Department of Psychology, Loyola University Maryland, Baltimore, Maryland 3 Department of Psychiatry, The Center for Eating Disorders at Sheppard Pratt, Baltimore, Maryland Correspondence Kimberly P. Anderson, Department of Psychology, The Center for Eating Disorders at Sheppard Pratt, 6535 North Charles Street, Suite 300, Baltimore, MD 21204. Email: kanderson@sheppardpratt.org Abstract Objective: The aim of this randomized controlled trial with a parallel design was to evaluate the effect of brief, cognitive remediation therapy (CRT) for anorexia nervosa (AN) on set-shifting. Method: Two hundred seventy-five inpatient adults and adolescents with AN (mean age = 23.1; SD = 12.7) were randomly assigned (using simple randomization proce- dures) to either a CRT or control condition. All participants received treatment as usual; however, the CRT condition completed five CRT group sessions in lieu of other group therapies provided on the unit. Set-shifting abilities were evaluated by: (a) neuropsychological measures and (b) experimental cognitive behavior therapy thought records. Blinding of group assignment occurred during baseline assessment and ended following group commencement. Results: Data from 135 CRT and 140 control condition participants were analyzed. On all neuropsychological measures, results revealed no between group condition effects, but did show statistically significant time effects, with medium to large effect sizes. Thought record analysis revealed a significant condition by age interaction effect where adults in the CRT condition generated significantly more alternative thoughts and had stronger believability of alternative thoughts than children, a trend that was not found in the control condition. This yielded moderate to large effect sizes of.0.56 and 0.72, respectively. Discussion: Based on traditional neuropsychological measures, these findings do not suggest a differential effect of CRT for AN in the format applied. However, results suggest that CRT may have some increased beneficial cognitive effect for adults, as compared to children, based on thought record analysis. KEYWORDS anorexia nervosa, cognitive flexibility, cognitive remediation, eating disorder, set-shifting, thought record, treatment Received: 21 February 2019 Revised: 13 June 2019 Accepted: 4 July 2019 DOI: 10.1002/eat.23143 Int J Eat Disord. 2019;1–11. wileyonlinelibrary.com/journal/eat © 2019 Wiley Periodicals, Inc. 1