Treatment-Resistant Obsessive-Compulsive Disorder (OCD): Focus on Antipsychotic Augmentation to SRIs

Introduction: Obsessive-Compulsive Disorder (OCD) is a common psychiatric illness with lifetime prevalence in the general population of approximately 2-3%. Serotonin Reuptake Inhibitors (SRIs) and Cognitive- Behavioral Therapy (CBT) in the form of Exposure and Response Prevention (ERP) both represent first-line treatments for OCD. However, unsatisfactory response to these treatments is common and the evaluation of next-step treatment strategies is highly relevant. Antipsychotic augmentation is the most studied pharmacological strategy. The purpose of this review is to provide guidance regarding the choice of antipsychotic medication on the basis of current evidence. Material and Methods: We carried out a search on MEDLINE/PUBMED database, selecting meta-analyses, systematic reviews and randomized controlled studies written in English on antipsychotic augmentation of treatment resistant OCD. We also considered open-label studies and case series, written in English. We reviewed the available evidence for antipsychotic use in treatment-resistant-OCD. Results: Antipsychotic addition to SRI treatment is supported by a positive number of double-blind studies although differences between them seem to exist. Fourteen double blind, randomized, placebo controlled trials investigating quetiapine (N=5), risperidone (N=3), olanzapine (N=2), aripiprazole (N=2), haloperidol (N=1), paliperidone (N=1) were identified. Significant efficacy was identifiable for risperidone and aripiprazole but not for quetiapine and olanzapine. Results regarding haloperidol and paliperidone were inconsistent. Discussion: Overall, about 50% of SRI-resistant-OCD patients benefited from augmentation strategy with antipsychotic. Risperidone and aripiprazole can be considered as the agents of first choice and should be preferred to the others antipsychotic. In our opinion, olanzapine may be a valid alternative to risperidone. Further trials are required to optimize pharmacological treatment for SRI-resistant-OCD.