Double-blind, placebo-controlled, pilot trial of paliperidone augmentation in serotonin reuptake inhibitor-resistant obsessive-compulsive disorder.

OBJECTIVE: This pilot study explored the efficacy and tolerability of paliperidone augmentation of serotonin reuptake inhibitors (SRIs) in adults with treatment-resistant obsessive-compulsive disorder (OCD).

METHOD: Thirty-four patients aged 24-67 years (mean = 43.7 years, SD = 11.4) who met DSM-IV criteria for OCD and remained symptomatic following 2 or more past adequate SRI trials (including their current medication) were enrolled from May 2008 to March 2012. Participants were treated for 8 weeks in a double-blind study with either paliperidone (up to 9 mg/d) or matching placebo in addition to their SRI. Blinded raters conducted outcome assessments. The primary outcome, obsessive-compulsive symptom severity, was assessed using the Yale-Brown Obsessive Compulsive Scale (YBOCS). Secondary outcomes included the Clinical Global Impressions-Severity of Illness and -Improvement scales.

RESULTS: Paliperidone administration resulted in significant baseline-to-posttreatment reductions in obsessive-compulsive symptoms as measured by the YBOCS (P < .01, d = 0.66), although placebo administration also resulted in medium-sized, trend-level significant YBOCS changes (P = .05, d = 0.53). In exploratory analyses examining between-group differences, tests for paliperidone superiority relative to placebo were not significant (P = .14, d = 0.34); however, a numerical trend toward significant between-group differences was found, with a reduction of 7.98 points on the YBOCS for the paliperidone group compared to a reduction of 4.02 points for the placebo group. Paliperidone was generally well tolerated and not associated with significant weight gain (mean [SD] weight: paliperidone, pretreatment 84.70 [27.08] kg, posttreatment 84.84 [18.99] kg; vs placebo, pretreatment 77.50 [25.33] kg, posttreatment 77.43 [19.90] kg; P = .21).

CONCLUSIONS: These results suggest that paliperidone augmentation is well tolerated and has potential efficacy in the short-term treatment of some patients with SRI-resistant OCD. Well-powered, randomized, controlled studies are necessary to more definitively address the efficacy of this treatment strategy.

TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00632229.