Variants of exposure and response prevention in the treatment of obsessive-compulsive disorder: A meta-analysis

Consistent findings suggest that exposure and response prevention (ERP) procedures are highly effective in treating obsessive-compulsive disorder (OCD). However, the studies that have reported success with this intervention have employed numerous variations in treatment procedures. Four general variations have been (1) whether the exposure sessions were supervised by the therapist or conducted by the patient on his or her own, (2) whether in vivo or imaginal exposure was used, (3) whether exposure stimuli were presented, beginning with the least or the most anxiety-evoking, and (4) whether response prevention involved the complete or partial abstinence from ritualizing. Whereas a few authors have addressed the relative efficacy of these procedural variations within single studies, results have been largely equivocal. We employed meta-analytic methods to quantitatively examine the degree of symptom improvement associated with the aforementioned variations of ERP. A total of 38 trials from 24 controlled and uncontrolled studies were included in the metaanalysis. Effect sizes were calculated as the standardized within-group change from pre- to posttreatment, a procedure that varies from traditional meta-analytic methods and likely yielded inflated estimates of treatment efficacy. Our results suggested that therapist-supervised exposure was more effective than self-controlled exposure. Further, the addition of complete response prevention to exposure therapy was associated with better outcome than partial or no response prevention. In reducing symptoms of anxiety, the combination of in vivo and imaginal exposure was superior to in-vivo exposure alone. Findings are discussed in terms of advancing the effectiveness of ERP in the treatment of OCD.