Internet cognitive behavioural treatment for obsessive compulsive disorder: A randomised controlled trial Alison E.J. Mahoney a, * , Anna Mackenzie a, b , Alishia D. Williams a, b , Jessica Smith a , Gavin Andrews a, b a Clinical Research Unit for Anxiety and Depression (CRUfAD), St. Vincent's Hospital, Level 4 O'Brien Centre, 394-404 Victoria Street, Darlinghurst, Sydney, New South Wales, 2010, Australia b School of Psychiatry, UNSW Medicine, University of New South Wales, Sydney, NSW, 2052, Australia article info Article history: Received 29 July 2014 Received in revised form 19 September 2014 Accepted 29 September 2014 Available online 7 October 2014 Keywords: Obsessive compulsive disorder Internet-based cognitive behaviour therapy Cognitive behaviour therapy abstract Internet-based cognitive behaviour therapy (iCBT) is becoming increasing accepted as an efficacious and effective treatment for the anxiety and depressive disorders. However few studies have examined the efficacy of iCBT for obsessive compulsive disorder (OCD). This randomised controlled trial compared technician-administered iCBT (n ¼ 32) to a treatment as usual (TAU) control group (n ¼ 35) in patients with OCD. The primary outcome measures were the Dimensional Obsessive-Compulsive Scale (DOCS) and the Obsessional Beliefs Questionnaire (OBQ-20) administered at pre- and post-treatment (or matched time points). The iCBT group was followed-up at 3-months post-treatment when diagnostic status was assessed at clinical interview. The iCBT program was more efficacious than TAU in reducing maladaptive OC beliefs as well as symptoms of OCD, distress, and depression, with large within- and between-groups effect sizes found (>.78). Adherence was high (75%) and gains were maintained at 3 month-follow-up with 54% of treatment completers no longer meeting diagnostic criteria for OCD at follow-up. These results are comparable to outcomes obtained by clinician-administered face-to-face and internet-based programs and suggest that iCBT for OCD is efficacious when administered by a clinically- supervised technician. Future research is now needed to evaluate how effective iCBT for OCD is in routine clinical settings. © 2014 Elsevier Ltd. All rights reserved. Individuals with obsessive compulsive disorder (OCD) experi- ence persistent, intrusive, and ego-dystonic obsessions (recurrent thoughts, urges, or images) and/or compulsions (repetitive behav- iours or mental acts performed to relieve distress) (American Psychiatric Association [APA], 2013). The disorder has an esti- mated annual prevalence of 0.6e1.8% and is associated with sub- stantial psychiatric comorbidity, disability, and economic costs (APA, 2013; Andrews, Henderson, & Hall, 2001; Crino, Slade, & Andrews, 2005; DuPont, Rice, Shiraki, & Rowland, 1995). Although cognitive behaviour therapy (CBT) and antidepressant medications are established evidence-based treatments (Fineberg, Reghunandanan, Brown, & Pampaloni, 2013; National Institute for Health and Clinical Excellence, 2005; Olatunji, Davis, Powers, & Smits, 2013), many individuals with OCD remain untreated, receive inappropriate treatment, or delay seeking treatment for many years (Andrews et al., 2001; Marques et al., 2010). Internet-based cognitive behaviour therapy (iCBT) aims to reduce the barriers associated with accessing traditional face-to- face treatment; barriers such as cost, inconvenience, social stigma, and personal embarrassment (Marques et al., 2010; Wootton, Titov, Dear, Spence, & Kemp, 2011). Andrews, Cuijpers, Craske, McEvoy, and Titov (2010) found that iCBT for anxiety and depressive disorders demonstrated comparable efficacy to face-to- face CBT in their meta-analysis of 22 randomised controlled trials (RCT). However, the evidence base for iCBT for people with OCD is limited. Baer and colleagues developed the first comprehensive computerised behaviour therapy program for OCD, BT Steps (Baer & Greist, 1997). Initially the program was delivered via a standardised workbook and a telephone-based automated interactive voice- response system. The largest RCT (N ¼ 218) evaluating BT Steps found that the program (within group d ¼ .84) was marginally less effective than clinician-guided behaviour therapy (d ¼ 1.22) but more effective than relaxation therapy (d ¼ .35) in improving * Corresponding author. Tel.: þ61 2 8382 1407; fax: þ61 2 8382 1402. E-mail addresses: amahoney@stvincents.com.au (A.E.J. Mahoney), alishia. williams@unsw.edu.au (A.D. Williams), Smith@svha.org.au (J. Smith), gavina@ unsw.edu.au (G. Andrews). Contents lists available at ScienceDirect Behaviour Research and Therapy journal homepage: www.elsevier.com/locate/brat http://dx.doi.org/10.1016/j.brat.2014.09.012 0005-7967/© 2014 Elsevier Ltd. All rights reserved. Behaviour Research and Therapy 63 (2014) 99e106