A randomised controlled trial of group cognitive behavioural therapy for perfectionism Alicia K. Handley * , Sarah J. Egan, Robert T. Kane, Clare S. Rees School of Psychology and Speech Pathology, Faculty of Health Sciences, Curtin University, Australia article info Article history: Received 22 December 2013 Received in revised form 5 February 2015 Accepted 21 February 2015 Available online 25 February 2015 Keywords: Perfectionism Group Cognitive behavioural therapy abstract Perfectionism is associated with symptoms of anxiety disorders, eating disorders and mood disorders. Treatments targeting perfectionism may reduce the symptoms of these disorders (Egan, Wade, & Sha- fran, 2011). This study is the first randomised controlled trial to investigate the efficacy of group cognitive behavioural therapy (CBT) for perfectionism. Forty-two participants with elevated perfectionism and a range of anxiety, eating and mood disorders were randomised to group CBT for perfectionism or a waitlist control. The treatment group reported significantly greater pre-post reductions in perfectionism, symptoms of depression, eating disorders, social anxiety, anxiety sensitivity and rumination, as well as significantly greater pre-post increases in self-esteem and quality of life compared to the waitlist control group. The impact of treatment on most of these outcomes was mediated by pre-post change in perfectionism (Concern over Mistakes). Treatment gains were reliable and clinically significant, and were maintained at 6-month follow-up. Findings support group CBT for perfectionism being an efficacious treatment for perfectionism and related psychopathology, as well as increasing self-esteem and quality of life. © 2015 Elsevier Ltd. All rights reserved. Perfectionism involves setting demanding standards and having a significant concern over mistakes (Frost, Marten, Lahart, & Rosenblate, 1990). This definition has primarily arisen from the results of factor analytic studies of multidimensional perfectionism measures (Frost et al., 1990; Hewitt & Flett, 1991) as opposed to being based on theoretical descriptions of the construct (Shafran, Cooper, & Fairburn, 2002). Perfectionism has been identified as an important factor in the onset, severity and maintenance of anxiety, mood and eating disorders (Egan, Wade, & Shafran, 2011). It can account for the co-morbidity of disorders (Bieling, Summerfeldt, Israeli, & Antony, 2004) and can negatively impact treatment (e.g., Blatt, Quinlan, Pilkonis, & Shea, 1995). Conse- quently, perfectionism has been argued to be a transdiagnostic process (Egan et al., 2011). This implies that treatments targeting perfectionism may not only reduce perfectionism but also the symptoms of related disorders (Egan et al., 2011). Several studies have examined the efficacy of cognitive behav- ioural therapy (CBT) for perfectionism (CBT-P) and the results so far are promising. A recent meta-analysis examined the outcomes of eight studies of CBT-P and found large pooled effect sizes for pre- post treatment reductions in perfectionism and medium pooled effect sizes for pre-post treatment reductions in depression and anxiety (Lloyd, Schmidt, Khondoker, & Tchanturia, 2014). Only two of the studies included in the meta-analysis were RCTs examining the efficacy of CBT-P in clinical samples. Riley, Lee, Cooper, Fairburn, and Shafran (2007) found in a sample of participants, of whom 70% met diagnoses of anxiety and depression, that CBT-P resulted in significant reductions in Clinical Perfectionism Questionnaire (CPQ; Fairburn, Cooper, & Shafran, 2003) scores relative to a waitlist control condition. Post-treatment reductions in perfectionism, anxiety and depression were maintained at 4-month follow-up. Clinically significant change in perfectionism occurred in 75% of participants and the number of anxiety and depression diagnoses halved at post-treatment. Steele and Wade (2008) examined the efficacy of guided self-help CBT-P relative to standard CBT for Bulimia Nervosa (BN; Cooper, 1993, in Steele & Wade, 2008) and mindfulness (Segal, Williams, & Teasdale, 2002) in individuals with BN and Eating Disorder Not Otherwise Specified (EDNOS). Partici- pants in all conditions demonstrated significant decreases in perfectionism, depression and eating disorder symptoms and sig- nificant increases in self-esteem between pre- and post-treatment. CBT-P tended to produce larger effect sizes for co-morbid anxiety * Corresponding author. School of Psychology and Speech Pathology, Curtin University, GPO Box U1987, Perth, Western Australia, 6845, Australia. E-mail address: A.Handley@curtin.edu.au (A.K. Handley). Contents lists available at ScienceDirect Behaviour Research and Therapy journal homepage: www.elsevier.com/locate/brat http://dx.doi.org/10.1016/j.brat.2015.02.006 0005-7967/© 2015 Elsevier Ltd. All rights reserved. Behaviour Research and Therapy 68 (2015) 37e47