Olanzapine in the treatment of pathological gambling: a negative randomized placebo-controlled trial.

Author(s): McElroy SL, Nelson EB, Welge JA, Kaehler L, Keck PE Jr

Affiliation(s): Psychopharmacology Research Program, Department of Psychiatry, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267-0559, USA. susan.mcelroy@uc.edu

Publication date & source: 2008-03, J Clin Psychiatry., 69(3):433-40.

Publication type: Randomized Controlled Trial; Research Support, Non-U.S. Gov't

OBJECTIVE: Pathological gambling is associated with bipolar disorder and dopamine dysfunction. Olanzapine is a second-generation antipsychotic with mood-stabilizing properties and antagonistic activity at several dopamine receptors. The purpose of this study was to evaluate olanzapine in the treatment of pathological gambling. METHOD: In this 12-week, single-center, randomized, double-blind, placebo-controlled, flexible-dose (2.5-15 mg/day) trial, 42 outpatients with pathological gambling by DSM-IV-TR criteria received olanzapine (N = 21) or placebo (N = 21). The primary outcome measure was the Pathological Gambling Adaptation of the Yale-Brown Obsessive Compulsive Scale (PG-YBOCS). The primary analysis of efficacy was a longitudinal analysis of the intent-to-treat sample, with treatment-by-time interaction as the effect measure. Subjects were enrolled from June 2, 2000, through November 28, 2005. RESULTS: Compared with placebo, olanzapine was associated with a similar rate of reduction in total scores on the PG-YBOCS scale, as well as in gambling episodes/week, hours gambled/week, and Clinical Global Impressions-Severity of Illness scale scores. The mean (SD) olanzapine daily dose at endpoint evaluation was 8.9 (5.2) mg/day. Eleven subjects (52%) receiving olanzapine and 6 (29%) receiving placebo discontinued prematurely; 3 subjects receiving olanzapine and 2 receiving placebo discontinued because of adverse events. Events causing olanzapine discontinuation were pneumonia, sedation, and hypomania. CONCLUSION: Olanzapine was not superior to placebo in the short-term treatment of pathological gambling. It was also associated with a high discontinuation rate. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT00438776 (http://www.clinicaltrials.gov).