Dopamine antagonists in tic-related and psychotic spectrum obsessive compulsive disorder.

Serotonin uptake inhibitors (SUIs) have been established as the first-line pharmacotherapy of obsessive compulsive disorder (OCD). However, approximately one half of patients who receive an adequate trial with these agents remain clinically unchanged. The addition of drugs that enhance serotonin (5-HT) neurotransmission, such as lithium and buspirone, to ongoing treatment in SUI-refractory patients has generally proved to be an ineffective strategy. The addition of dopamine antagonists to the regimens of SUI-resistant patients appears to be a useful approach for OCD patients with a comorbid chronic tic disorder (e.g., Tourette's syndrome) and possibly for those with concurrent psychotic spectrum disorders. These drug response data suggest that both the 5-HT and dopamine systems may be involved in the treatment, and possibly the pathophysiology, of specific subtypes of OCD.