Possible Dose-Response Relationship for Risperidone in Obsessive-Compulsive Disorder

Sir: Stein and colleagues1 described 8 patients with obsessive-compulsive disorder (OCD) previously refractory to serotonin reuptake inhibitor (SRI) treatment who substantially improved after treatment augmentation with risperidone. Although it is impressive that 37.5% of these subjects improved much to very much, Saxena and colleagues made an even more dramatic report of clinically significant improvement in 67% of 21 SRI-refractory OCD patients after risperidone augmentation of the SRI. Caution is in order when comparing Stein and colleagues’ retrospective case series with Saxena and colleagues’ uncontrolled open trial, but it is striking that Saxena’s group employed a risperidone dose more than twice that used by Stein’s group (mean daily dose, 2.75 mg vs. 1.25 mg).