Researchers have discovered how to determine which bipolar patients will benefit from Ketamine, a treatment commonly used for depression and pain relief, according to a study presented at the ANESTHESIOLOGY™ 2013 annual meeting.

Two-thirds of patients benefit from Ketamine and using a blood test, researchers can predict which patients will respond favorably.

"Doctors know that very small doses of Ketamine help relieve depression and pain," said Michael Goldberg, M.D., professor and chairman of anesthesiology, and associate dean for education at Cooper Medical School of Rowan University and chief of the Department of Anesthesiology for Cooper University Health Care, Camden, N.J. "But one in three patients do not respond to this treatment. This research will help as we seek ways to provide these patients relief."

Researchers identified the compound that Ketamine breaks down into, which they named HNK (2S, 6S hydroxynorketamine). Additionally, researchers discovered the pattern or 'fingerprint' in the fatty acids of the blood that indicates which patients will respond to HNK.

In the study, 22 patients with bipolar disorder were given intravenous doses of Ketamine. Blood was collected from each patient. Responders and non-responders were identified using a standardized depression rating scale. A positive response was defined as a 50 percent or greater improvement. Additionally, researchers examined metabolic patterns in blood samples.

Researchers discovered there was a difference in how responders and nonresponders metabolized fatty acids, based on the variability in levels of 18 different metabolites.

"These are significant discoveries which should eventually help in the treatment of patients suffering from depression and chronic pain," said Irving Wainer, Ph.D., senior investigator with the Intramural Research Program at the National Institute on Aging, Baltimore. "The next step is to look for the genetic or environmental factors that determine whether a person develops the metabolic pattern that responds to the treatment. We hope this leads to the development of customized or individualized treatment for each patient."