Background
Bipolar disorder is a lifelong episodic condition characterized by mood swings between mania and depression. Several lines of evidence suggest that serotonin is likely to play a pivotal role in the pathophysiology of bipolar disorder. Ritanserin, a 5-HT2 receptor antagonist, has been reported to have antipsychotic activity. In this 6-week double blind, placebo controlled study involving moderate to severe manic patients, we assessed the effects of ritanserin plus haloperidol in combination with lithium.