Antipsychotics in treatment-resistant Obsessive-Compulsive Disorder: which antipsychotic, which dose and how long antipsychotic addition should be maintained

Objectives: Treatment-resistant Obsessive-Compulsive Disorder (OCD) patients are defined as those who undergo adequate trials of first-line therapies without achieving a satisfactory response. First line treatments for OCD include both serotonin reuptake inhibitors (SRIs) and cognitive behavior therapy (CBT). Because of the high number of OCD patients not responding to first-line treatments (40-60%) and considering the even greater prevalence rate of residual symptoms and significant impairment shown in patients previously described as “clinical responders”, the question of the proper treatment of resistant OCD is a clinically meaningful and a practical issue for psychiatrists. Antipsychotic augmentation proved to be an effective strategy for resistant OCD. However, there are unresolved questions concerning which antipsychotic is effective (or more effective) and how antipsychotics should be used in terms of doses and duration of treatment. The purpose of this study is to systematically review available studies on antipsychotic augmentation for treatment-resistant OCD, in order to guide the practical choice. Materials and methods: We searched on PubMed, Psychnet and Cochrane Libraries from inception to January 2016. Articles published in English and related to the use of antipsychotics in OCD were considered. We evaluated meta-analyses, systematic reviews and randomized controlled trials of adult patients with treatment-resistant OCD. Results: Antipsychotic augmentation is an evidence-based option for treatmentresistant OCD, with a response rate of approximately 50% within the first 4-to6 weeks. Aripiprazole (10-15 mg/day) and risperidone (0.5-2 mg/day) are effective, olanzapine (10 mg/day) is possibly effective. Haloperidol addition is also a viable option, particularly in patients with comorbid tic disorders. Given results of studies performed to date quetiapine should be regarded as non-effective. Preliminary results from open label studies suggest that antipsychotic augmentation, once effective, should be maintained in order to maintain remission. Conclusions: Not all antipsychotics are effective as add-on treatments in resistant OCD. Characteristics of patients and side effects generally associated with each different antipsychotic may guide the practical choice. Further research is required concerning the comparative effectiveness among antipsychotics, the optimal target dose and the ideal duration of antipsychotic addition. In our opinion, antipsychotic augmentation in patients who responded to this treatment should be maintained in order to prevent relapses. However, clinicians must remember patients’ exposure to the common and serious adverse effects associated with long-term antipsychotic administration, especially metabolic disturbances.