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 = 32) to a treatment as usual (TAU) control group (n = 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.
