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.