Background: The prevalence of obsessive-compulsive symptoms (OCS) in patients with schizophrenia is relatively high. Antipsychotics have been found to influence OCS.
Objective: To determine whether induction or severity of OCS differs during treatment with olanzapine or risperidone in young patients with early psychosis.
Methods: One hundred twenty-two patients with a Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition diagnosis of schizophrenia, schizoaffective disorder, or schizophreniform disorder were randomized in a double-blind design to groups of 6 weeks' treatment with olanzapine (n = 59) or risperidone (n = 63), with a mean dose of 11.3 mg olanzapine and 3.0 mg risperidone at 6 weeks. Primary outcome measures were the mean baseline-to-endpoint change in total score on the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS).
Results: Treatment with olanzapine was associated with greater decreases in Y-BOCS total score than treatment with risperidone in total group (N = 122: -2.2 vs -0.3, z = -2.651, P < 0.01), in patients with baseline Y-BOCS total score greater than 0 (n = 58: -5.1 vs -0.4, z = -2.717, P < 0.01), and in patients with baseline Y-BOCS total score greater than 10 (n = 29: -7.1 vs -0.6, z = -2.138, P = 0.032).
Conclusions: In this randomized, 6-week, double-blind trial, we found a significant and clinically relevant difference in decrease in Y-BOCS scores favoring olanzapine compared with risperidone.