Reid, J.E., Laws, K.R., Drummond, L., Vismara, M. Grancini, B., Mpavaenda, D., Fineberg, N.A. (2021). Cognitive behavioural therapy with exposure and response prevention in the treatment of obsessive-compulsive disorder: A systematic review and meta-analysis of randomized controlled trials. Comprehensive Psychiatry, 106, 152223. https://doi.org/10.1016/j.comppsych.2021.152223.
Cognitive-behavioural therapy (CBT) combined with exposure and response prevention (ERP) is considered by many the treatment of choice for obsessive-compulsive disorder (OCD). However, questions remain about the size of its effects, the reliability of the research, and the relative efficacy of CBT plus ERP compared to other psychological treatments. Reid and colleagues conducted a systematic review and meta-analysis of randomized controlled trials of CBT with ERP in patients of all ages with OCD. They included 36 studies with 2000 patients (537 children/adolescents and 1483 adults) receiving treatment and 1015 in control conditions. When compared against all control conditions, CBT with ERP showed a significant and large effect (g = 0.74: 95% CI = 0.51 to 0.97 k =36). While CBT with ERP was more effective than a “psychological placebo” (e.g., progressive relaxation; g = 1.13: 95% CI 0.71 to 1.55, k = 10) and no treatment control conditions (g = 1.27: 95% CI 0.79 to 1.75), it was no more effective than other active forms of psychological therapy (g = −0.05: 95% CI −0.27 to 0.16, k = 8). When compared to pharmacological treatment with an adequate dosage of selective serotonin reuptake inhibitors, CBT with ERP was marginally better with a small effect (g = 0.32: 95% CI -0.00 to 0.64, p = 0.05). Researcher allegiance or bias had a big impact on the effects of CBT with ERP. Researcher allegiance refers to studies conducted by researchers who prefer, favour, or have a vested interest in the treatment they are testing. In the studies identified as having researcher allegiance, a large favourable effect for CBT with ERP emerged (g = 0.95: 95% CI 0.69 to 1.2). By contrast, in trials where the authors did not identify researcher allegiance (k= 8), CBT with ERP showed no significant effects (g = 0.02: 95% CI−0.29 to 0.33). This difference was statistically significant (Q = 20.33, p < 0.005). There was no evidence of publication bias, but 28 of the 36 studies had a high risk of bias (in which there were deficiencies in the research design, procedures, or data analyses).
At this point, CBT plus ERP is the most studied treatment for OCD, and it appears to be effective in reducing symptoms post-treatment. However, this meta-analysis raises more questions than it answers about the reliability of the research. Other active treatments (e.g., CBT without ERP) appear just as effective, which suggests that ERP may not be necessary to treat OCD. Researchers who favor or have a vested interest in CBT plus ERP produce much larger effects for their preferred treatment, and the quality of most of the research is low. Such findings lower one’s confidence in the conclusions drawn from the research.