Cognitive-behavioural therapy is an effective treatment for obsessive-compulsive disorder (OCD). However, there are many barriers in accessing this treatment, with stigma being a particularly prominent barrier for many patients. Self-guided internet-delivered cognitive-behavioural therapy (ICBT), which does not require any contact with a therapist, has the potential to overcome this barrier. However, there is limited research on the efficacy of self-guided ICBT for OCD. The aim of the current study was to examine the efficacy of self-guided ICBT for OCD in a large international sample. Two hundred and sixteen participants were included in the study (Mage = 34.00; SD = 12.57; 72.7% female). On the primary outcome measure, the Yale-Brown Obsessive-Compulsive Scale (YBOCS), a medium within-group effect size was found from pre-treatment to post-treatment (g = 0.63), and a large within-group effect size was found from pre-treatment to 3-month follow-up (g = 0.98). Approximately one-quarter to one-third of participants met criteria for clinically significant improvement at post-treatment and 3-month follow-up (11% and 17% met criteria for remission at post-treatment and 3-month follow-up, respectively). These results demonstrate that self-guided ICBT may be an efficacious treatment for individuals with OCD who cannot or do not wish to engage with a mental health professional, resulting in medium to large effect sizes.
Keywords: CBT; OCD; Obsessive-compulsive disorder; cognitive behavioural therapy; internet-delivered treatment; treatment barriers.