Obsessive–compulsive disorder (OCD) is a chronic and often disabling disease. Patients affected by OCD often do not respond to specific pharmacological treatments: despite the effectiveness of clomipramine and selective serotonin reuptake inhibitors (SSRIs) such as paroxetine, citalopram, sertraline, fluoxetine, and fluvoxamine, approximately 40% to 60% of patients who receive an adequate treatment with these agents are clinically unchanged (1). Thus, alternative strategies are needed. In this regard, the association of neuroleptics such as haloperidol (2) and pimozide (3) appears to be a potentially useful strategy for a subgroup of patients, especially those with comorbid chronic tic disorders (such as Tourette syndrome) or schizotypal personality disorder (4). Although, however, this strategy has been shown to be effective for up to 65% of SSRI-refractory patients with OCD (2), the chronic administration of traditional antipsychotics often leads to such undesirable side effects as tardive dyskinesia. To prevent the onset of these phenomena and to increase patients’ compliance, atypical neuroleptics (drugs with a safer side-effects profile) have been investigated in the management of this disorder.

Risperidone has shown efficacy as adjunctive treatment in SSRI-refractory OCD (5,6), but these studies were performed

Manuscript received March 2000, revised, and accepted March 2001.
¹Medical Director, Department of Psychiatry, Center for Treatment of Anxiety Disorders, Morbegno, Italy.
Address for correspondence: Dr Giorgio Francobandiera, Azienda Sanitaria Locale della Provincia di Sondrio, Presidio di Morbegno, Piazza S. Antonio 2. 23017 Morbegno (SO), Italy.
E-mail: giofran@katamail.com

on small samples with an open-label design. The only double-blind, placebo-controlled study (7) suggested that patients with OCD may respond to risperidone augmentation of ongoing fluvoxamine treatment and that comorbidity for tics or schizotypal personality disorder was not a predictor.

Clozapine treatment was found to be ineffective in cases of refractory OCD (8). Further, it seems to trigger obsessive–compulsive symptoms in patients affected by schizophrenia (9,10). Conversely, there are reports of patients with schizophrenia associated with obsessive–compulsive symptoms who do respond to a combination of clozapine and an SSRI (11).

Published data on olanzapine augmentation in cases of treatment-resistant OCD include 2 letters (12,13) and an open-label study (14) carried out by the same group. These authors concluded that olanzapine may effectively augment an ongoing SSRI medication in the treatment of refractory OCD but that there is a subgroup of patients who do not respond to this association.

We also, however, found reports suggesting the possible onset of obsessive symptoms in patients affected by schizophrenia who were treated with olanzapine alone (15,16). The purpose of this study is therefore to evaluate the effect of olanzapine augmentation in the management of SSRI-resistant OCD.

Methods

The subjects who entered the trial were 9 outpatients affected by refractory OCD. Diagnoses of OCD and comorbid psychiatric conditions were made by clinical interview, according to DSM-IV criteria.