Anesthetic Shows Promise for Bipolar Disorder: Single Injection of Ketamine Provides Relief

By: Katrina Woznicki

WebMD

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Anesthetic Shows Promise for Bipolar Disorder: Single Injection of Ketamine Provides

Relief From Depression in 40 Minutes.

Katrina Woznicki, WebMD, August 2, 2010.

Originally appeared at:

http://www.webmd.com/bipolar-disorder/news/20100802/anesthetic-shows-promise-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.

Ketamine and Bipolar Depression

It has been challenging to find treatments for bipolar disorder because scientists do

not fully understand the condition. However, recent research suggested the brain’s

glutamatergic system, which plays a role in information processing and memory, may be

involved in bipolar disorder. Ketamine affects this system and may have potential as a

new treatment, the researchers explain.

The research team studied 18 patients between the ages of 18 and 65 who had failed to

respond to other common treatments for bipolar disorder. The patients were randomly

assigned to receive either a single dose of ketamine or a placebo between October

2006 and June 2009. The patients had taken either valproate or lithium—two standard

treatments for bipolar depression—without success prior to beginning the study.

During the study, patients did not participate in any psychotherapy, but they did continue

to take valproate or lithium and were not allowed to receive any other depression drugs.

Two weeks after the first injection, the researchers switched the groups and gave them

the treatment they did not receive during the first round. There were no serious side

effects.

These findings are particularly noteworthy because a large number of the participants

had been prescribed complex treatment regimens in the past with substantial failures, the

authors write.

“The mean number of past antidepressant trials was seven, and more than 55 percent of

participants failed to respond to electroconvulsive therapy. The toll of this protracted and

refractory illness on the subjects was evident, in that two-thirds of participants were on

psychiatric disability and nearly all were unemployed.”

“Future studies should examine strategies for long-term maintenance of ketamine’s rapid

antidepressant response,” the authors conclude.

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