People with obsessive-compulsive disorder often remain symptomatic following psychological treatment: A clinical significance analysis of manualised psychological interventions.

Background: Previous meta-analyses conclude that efficacious psychological treatments for obsessive-compulsive disorder (OCD) exist. However, determining the efficacy of psychological treatments requires multiple forms of assessment. We conducted an individual patient data meta-analysis of randomised controlled trials (RCTs) of manualised psychological therapy for adults with OCD.

Methods: Four electronic databases were searched from their inception until July 2019. IPD were available for 24 (n = 1626) of 43 (n = 2455) eligible RCTs. Treatment efficacy was evaluated using clinical significance analyses (using standardised Jacobson methodology) and standardised mean difference within-group effect-size analyses. Outcomes were Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores at post-treatment and follow-up.

Results: At follow-up, large within-group effect sizes were found for treated patients (g = 1.45) and controls (g = 0.90). Treated patients were significantly more likely than controls to recover, but recovery rates were low; post-intervention, only 32% of treated patients and 3% of controls recovered; rising to 38% and 21% respectively at follow-up. Regardless of allocation, only 20% of patients were asymptomatic at follow-up. Individual cognitive therapy (CT) was most efficacious, followed by group CT plus exposure and response prevention. Self-help interventions were generally less efficacious than face-to-face approaches.

Limitations: Data were analysed from 24 of the 43 eligible RCTs. We were unable to consider the long-term efficacy of treatments because only two RCTs provided long-term (> 12 month) follow-up data.

Conclusion: Almost 80% of treated patients remain symptomatic. The efficacy of psychological interventions for patients with OCD must be enhanced.