Ketamine improved bipolar depression within minutes

May 31, 2012

Ketamine (credit: Wikimedia Commons)

A single dose of ketamine significantly improved depression symptoms for 79 percent of patients within 40 minutes, and remained improved over three days, researchers at the National Institute of Mental Health found. Now they’ve replicated that finding for patients with bipolar disorder.

Bipolar disorder is a serious and debilitating condition where individuals experience severe swings in mood between mania and depression. The episodes of low or elevated mood can last days or months, and the risk of suicide is high.

Importantly, and for the first time in a group of patients with bipolar depression, they also found that ketamine significantly reduced suicidal thoughts. These antisuicidal effects also occurred within one hour. Considering that bipolar disorder is one of the most lethal of all psychiatric disorders, these study findings could have a major impact on public health.

“Our finding that a single infusion of ketamine produces rapid antidepressant and antisuicidal effects within one hour and that is fairly sustained is truly exciting,” Dr. Zarate commented. “We think that these findings are of true importance given that we only have a few treatments approved for acute bipolar depression, and none of them have this rapid onset of action; they usually take weeks or longer to have comparable antidepressant effects as ketamine does.”

Ketamine is an N-methyl-D-aspartate (NMDA) receptor antagonist, which means that it works by blocking the actions of NMDA. Dr. Zarate added, “Importantly, confirmation that blocking the NMDA receptor complex is involved in generating rapid antidepressant and antisuicidal effects offers an avenue for developing the next generation of treatments for depression that are radically different than existing ones.”

Ref.: Carlos A. Zarate Jr. et al., Replication of Ketamine’s Antidepressant Efficacy in Bipolar Depression: A Randomized Controlled Add-On Trial,  Biological Psychiatry, 2012, DIU: 10.1016/j.biopsych.2011.12.010