Early Onset of Response With Selective Serotonin Reuptake Inhibitors in Obsessive-Compulsive Disorder

Selective serotonin reuptake inhibitors (SSRIs) are recommended as the first-line pharmacologic treatment for obsessive-compulsive disorder (OCD). SSRI response is thought to be delayed in OCD, even more so than in major depression. We conducted a meta-analysis to examine the trajectory of treatment response to SSRIs and how this trajectory is modulated by dosage.PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) were searched on May 22, 2013, for randomized, placebo-controlled SSRI trials in OCD with the search terms "serotonin uptake inhibitors" [MeSH] OR "serotonin uptake inhibitors" [Pharmacologic Action] AND "obsessive-compulsive disorder" [MeSH]. There were no language limitations on the search.Randomized, placebo-controlled trials that examined the efficacy of SSRIs in the treatment of adults with OCD and utilized the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) as an outcome were selected.We extracted weekly symptom data from randomized, placebo-controlled trials of SSRIs for the treatment of adults with OCD in order to characterize the trajectory of pharmacologic response. Our primary outcome was weighted mean difference on the Y-BOCS of SSRI treatment compared to placebo. We used the PROC MIXED procedure in SAS to examine 6 possible models of SSRI response. Interaction terms were utilized to examine the effect of dose, individual agent, and year of publication on SSRI response.The meta-analysis included 17 trials of SSRIs including 3,276 subjects. A statistically significant benefit of SSRIs compared to placebo was seen within 2 weeks after the start of treatment (weighted mean difference = -0.91 [95% CI, -0.54 to -1.28], P < .001). A logarithmic response curve, indicating decreasing symptom improvement over time, provided the best fit for the trajectory of OCD symptom improvement. A significantly greater response was associated with using higher doses of SSRIs (P < .0001).These results suggest that the greatest incremental treatment gains in OCD are seen early on in SSRI treatment. This is consistent with a previous meta-analysis examining time course of SSRI action in major depressive disorder and contrasts with the widely held belief that SSRI response in OCD is delayed.