Cognitive-behavioural therapy (CBT) is the first-line psychological treatment for obsessive-compulsive disorder (OCD). However, most individuals suffering from OCD do not receive CBT. An innovative approach to improve access to evidence-based care is the use of the Internet to deliver effective treatments. Therapist-guided Internet-based cognitive-behavioural therapy (iCBT) involves the administration of structured online lessons that provide the same information and skills typically taught in clinician-administered CBT, often with email support from a therapist. Accumulating evidence on iCBT for OCD has been produced, but a meta-analysis has not been conducted.

Through meta-analytic methods, the present study summarized evidence on iCBT for OCD.

Efficacy on OCD symptoms and comorbid depression versus control conditions at post-treatment and follow-up was evaluated.

A PRISMA meta-analysis was performed on randomized controlled trials. Treatments were classified as iCBT if they included CBT components for OCD (eg, exposure and response prevention) delivered through the Internet with or without email/phone support from a therapist.

Four trials were included (n = 238), which were classified at low bias risk. At post-treatment iCBT outperformed control conditions with a high effect size on OCD symptoms (d = 0.85, P<.05) and a medium on comorbid depression (d = 0.52, P<.05). Treatment effects were stable at 4-month follow-up with a high effect size on OCD (d = 1.45, P<.05), but not on comorbid depression (d = 0.33, P<.05).

iCBT seems a promising treatment modality for OCD. Further trials should assess log-term outcomes and effects on quality of life.

The authors have not supplied their declaration of competing interest.