Quetiapine augmentation to SRIs for patients with obsessive compulsive disorder: a double-blind, placebo-controlled study.

Background:

Although serotonin reuptake inhibitors (SRIs) are the most effective pharmacologic treatment currently available for patients with obsessive-compulsive disorder (OCD), 40% to 60% of patients do not respond to this treatment.

This study was conducted to evaluate the efficacy and tolerability of quetiapine in addition to an SRI for medication-naive or free patients with OCD.




Methods:

Ninety patients with primary OCD according to DSM-IV criteria will be recruited between November 2003 and December 2005 and randomly assigned in a 10-week, double-blind, placebo-controlled trial to receive dosages titrated upward to 450 mg/day of quetiapine (N = 45) or placebo (N = 45) in addition to their SRI treatment.
During the study, primary efficacy will be assessed according to change from baseline on the Yale-Brown Obsessive Compulsive Scale (Y-BOCS). A responder is defined as having a final Clinical Global Impressions-Improvement scale rating of "very much improved" or "much improved" and a decrease of > or = 25% in Y-BOCS score.

To determine the efficacy of quetiapine as an adjunct to patients with OCD, without comorbitity, who are newly diagnosed, medication-naive or free. The following hypotheses will be tested:

1. Addition of quetiapine to a SRI increases the number of responders to treatment;

2. Addition of quetiapine to a SRI decreases the time to response;

3. Addition of quetiapine to a SRI increases the effect size as measured with the YBOCS.

N/A

The trial will be a randomised, double-blind, placebo-controlled, fixed dose study with quetiapine as adjunct to a SRI administered at the maximum tolerable dosage. Fluoxetine and venlafaxine will be excluded.

Ninety patients with OCD will be recruited and randomly allocated to receive either an SRI with placebo or an SRI with quetiapine for 10 weeks.
Both patient and investigator will be blind to the drug assignment.