Anesthetic Shows Promise for Bipolar Disorder Aug. 2, 2010 -- Patients with bipolar disorder who failed to find relief from their depression with other standard treatments experienced fast-acting relief from a single intravenous (IV) dose of a drug called ketamine, according to a new, small study.

Researchers at the National Institute of Mental Health in Bethesda, Md., found that ketamine, an anesthetic, improved symptoms of depression within 40 minutes of injection. The beneficial effects remained significant one day and even two days after the injection, suggesting that ketamine was both fast-acting and long-lasting, the authors report in the August issue of Archives of General Psychiatry.

These results are noteworthy, the researchers say, since patients often experience a long lag between the time they take their depression treatment to the time they feel an improvement in their mood. Overall, 71% of the patients responded to the ketamine and reported an improvement in symptoms, compared with 6% of patients given a placebo.

Slideshow: Bipolar Disorder Overview