Internet-Based Cognitive Behavioural Treatments for Obsessive-Compulsive Disorder: A Systematic Review and Meta-Analysis.

Obsessive-compulsive disorder (OCD) is a common mental health condition characterized by distressing, intrusive thoughts (obsessions) and repetitive behaviours (compulsions) aimed at reducing anxiety. Internet-based cognitive behavioural therapy (ICBT) has emerged as an effective treatment modality for various mental health disorders. This meta-analysis evaluates the efficacy of guided self-help ICBT (GSH ICBT) and unguided self-help ICBT (SH ICBT) against active and passive control conditions in adults with OCD. A comprehensive systematic literature search yielded 12 randomized controlled trials (RCTs) comprising 15 comparison arms (N = 1416) that met the inclusion criteria. Results indicate that GSH ICBT significantly reduced OCD symptomatology posttreatment compared to active controls (g = 0.378, k = 9), with no significant effects maintained at follow-up (g = 0.153, k = 4). GSH ICBT was also found to be as effective as active CBT interventions in reducing comorbid anxiety and depression symptoms posttreatment (g = 0.278, k = 6) and at follow-up (g = 0.124, k = 4). However, improvements in quality of life were not significant posttreatment (g = 0.115, k = 4) nor at follow-up (g = 0.179, k = 3). Combined GSH and SH ICBT demonstrated large effects on reducing OCD symptoms (g = 0.754, k = 6), medium effects on comorbid symptoms (g = 0.547, k = 6) and small effects on quality of life (g = 0.227, k = 2) when compared to inactive controls. No significant differences were found between GSH and SH ICBT in all measured outcomes posttreatment (OCD: g = 0.098, k = 3; AD: g = 0.070, k = 3; QoL: g = -0.030, k = 1) and at follow-up (OCD: g = 0.265, k = 2; AD: g = 0.084, k = 2; QoL: g = 0.00, k = 1). Sample size was identified as a significant moderator of treatment effects. This paper further explores clinical significance, treatment adherence, therapist time investment and moderator influences of the ICBT. The limitations of the study and recommendations for future research are thoroughly discussed.