As many as half of
obsessive-compulsive disorder (OCD) patients treated with an adequate trial of
serotonin reuptake inhibitors (SRIs) fail to fully respond to treatment and continue to exhibit significant symptoms. Many studies have assessed the effectiveness of
antipsychotic augmentation in SRI-refractory OCD. In this systematic review, we evaluate the efficacy of
antipsychotic augmentation in treatment-refractory OCD. The electronic databases of PubMed, PsychINFO (1967-2005), Embase (1974-2000) and the Cochrane Central Register of Controlled Trials (CENTRAL, as of 2005, Issue 3) were searched for relevant double-blind trials using keywords '
antipsychotic agents' or '
neuroleptics' and '
obsessive-compulsive disorder'. Search results and analysis were limited to double-blind, randomized control trials involving the adult population. The proportion of subjects designated as treatment responders was defined by a greater than 35% reduction in Yale Brown Obsessive-Compulsive Scale (Y-BOCS) rating during the course of augmentation
therapy. Nine studies involving 278 participants were included in the analysis. The meta-analysis of these studies demonstrated a significant absolute risk difference (ARD) in favor of
antipsychotic augmentation of 0.22 (95% confidence interval (CI): 0.13, 0.31). The subgroup of OCD patients with comorbid
tics have a particularly beneficial response to this intervention, ARD=0.43 (95% CI: 0.19, 0.68). There was also evidence suggesting OCD patients should be treated with at least 3 months of maximal-tolerated
therapy of an SRI before initiating
antipsychotic augmentation owing to the high rate of treatment response to continued SRI monotherapy (25.6%).
Antipsychotic augmentation in SRI-refractory OCD is indicated in patients who have been treated for at least 3 months of maximal-tolerated
therapy of an SRI. Unfortunately, only one-third of treatment-refractory OCD patients show a meaningful treatment response to
antipsychotic augmentation. There is sufficient evidence in the published literature, demonstrating the efficacy of
haloperidol and
risperidone, and evidence regarding the efficacy of
quetiapine and
olanzapine is inconclusive. Patients with comorbid
tics are likely to have a differential benefit to
antipsychotic augmentation.