Quetiapine Augmentation in Obsessive-Compulsive Disorder Resistant to Serotonin Reuptake Inhibitors: An Open-Label Study

Background: The response of obsessive-compulsive disorder (OCD) to serotonin reuptake inhibitors (SRIs) is often inadequate. Case series reporting successful augmentation with risperidone and olanzapine led us to investigate quetiapine in OCD that was resistant to SRI treatment.

Method: In this 8-week, 2-site (S1, S2), open-label trial, 30 adults (16 at S1 and 14 at S2) with a DSM-IV diagnosis of OCD, SRI-resistant, received augmentation with quetiapine, with the dose doubled every 2 weeks from 25 mg to 200 mg/day. Primary outcome was measured with the Yale-Brown Obsessive Compulsive Scale (YBOCS). A response was defined as a >= 25% decrease from the baseline YBOCS score.

Results: Significant differences between the sites in patient characteristics (7/14 at S2 were hoarders, i.e., more treatment resistant, vs. 1/16 at S1; p = .01) and in quetiapine treatment (mean ± SD dose of 116 ± 72 mg/day at S2 vs. 169 ± 57 mg/day at S1; p = .039) necessitated separate analysis of results. At S1, the mean ± SD YBOCS score fell significantly from 27.7 ± 7.0 to 23.3 ± 8.4 (t = 2.96, df = 15, p = .01), and the responder rate was 31% (5/16). At S2, the mean YBOCS score did not decrease significantly, and the responder rate was 14% (2/14). Most adverse medication events were mild or moderate. Two subjects (13%) at S1 and 3 (21%) at S2 withdrew due to adverse events.

Conclusion: The results at S1 resemble those reported with other atypical antipsychotics and suggest that quetiapine augmentation may benefit treatment-resistant OCD. The poorer results at S2 may reflect the large proportion of hoarders or the less intense treatment. Longer, higher dose, large, double-blind, placebo-controlled comparison trials of atypical antipsychotics are needed.