Antipsychotic treatment in obsessive-compulsive disorder: a literature review

To review the role of antipsychotic medications in the treatment of obsessive-compulsive disorder (OCD); to explore current hypothesized conceptualizations of their mechanism of action; to highlight evolving interest in the validation of meaningful OCD subtypes within a heterogeneous spectrum of OCD, based on treatment response and other psychobiological variables.

A computerized literature search (MEDLINE: 1966 to December 2003, EMBASE: 1982 to December 2003) was used to locate relevant literature, using the terms obsessive-compulsive, antipsychotic and subtypes, with no restrictions imposed on searches.

Earlier studies of augmentation of serotonergic antidepressants (SRIs) with typical antipsychotics including haloperidol and pimozide in OCD demonstrated favourable responses, also highlighting patient subgroups with robust treatment response. Studies examining augmentation with atypical agents are emerging. SRI-resistant OCD patients are likely to benefit from augmentation with atypical antipsychotics in around 50% of cases.

While there is little role for antipsychotic monotherapy in OCD, there is growing evidence in support of adjunctive antipsychotics in OCD refractory to serotonin-reuptake inhibitors (SRIs). Further controlled trials are warranted. Particular subgroups of OCD patients, notably those with comorbid tic disorder and those with schizotypal personality disorder, have been shown to respond more robustly to augmentation strategies in some trials of both typical and atypical antipsychotics. Dopaminergic mediation with or without a moderating effect on serotonergic systems is likely to be important in the pharmacodynamic mechanisms of action of antipsychotic-SRI combinations in OCD.