The aim of the present study was to retrospectively review the charts of obsessive-compulsive disorder (OCD) patients who responded to the addition of an antipsychotic to the seroronin reuptake inhibitor (SRI), and who subsequently discontinued the antipsychotic, in order to evaluate whether antipsychotic discontinuation resulted in a relapse of the disorder. Charts of patients with a principal diagnosis of OCD (DSM-IV) treated with pharmacotherapy were reviewed in order to select patients who: (i) did not respond to a trial with a first-line drug (clomipramine or a selective SRI); (ii) received an antipsychotic at low doses (haloperidol, pimozide, risperidone or olanzapine) in order to potentiate the SRI; (iii) responded to this augmentation strategy; and (iv) discontinued the antipsychotic drug for any reason while continuing the SRI at the same dose. Relapse was defined as a worsening of Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) total score >/= 35% with respect to last evaluation before antipsychotic discontinuation or, for patients with a Y-BOCS < 16 at the end of the combination period, as a Y-BOCS total score >/= 16 at any time after antipsychotic discontinuation. According to our definition of relapse, 15 patients out of 18 (83.3%) relapsed after antipsychotic discontinuation, with a mean worsening of symptoms of 6.6 +/- 1.7 points in the Y-BOCS total score. Thirteen patients out of the 15 who relapsed did so by week 8 after discontinuation. Two subjects relapsed at the end of the 1-year study. Although retrospective, our study provides initial evidence that antipsychotic augmentation has to be maintained for patients who respond to this strategy, because the vast majority of subjects who discontinue the antipsychotic relapse within 2 months.