Researchers have identified the ketamine breakdown product that gives the drug its antidepressant effects, which could lead to faster, more-effective mood stabilizers in the future.

When the antidepressant effects of ketamine were first reported a decade ago, the anesthetic drug seemed likely to change the way doctors treat the most persistent cases of depression. Since 2006, the surgical drug has been shown to work in patients with treatment-resistant depression and provide relief much faster than mood stabilizers like SSRIs.

A chemical byproduct, or metabolite, created as the body breaks down ketamine likely holds the secret to its rapid antidepressant action, National Institutes of Health (NIH) scientists and grantees have discovered. This metabolite singularly reversed depression-like behaviors in mice without triggering any of the anesthetic, dissociative, or addictive side effects associated with ketamine.

Scientists say they have figured out how an experimental drug called ketamine is able to relieve major depression in hours instead of weeks.

Researchers from Yale and the National Institute of Mental Health say ketamine seems to cause a burst of new connections to form between nerve cells in parts of the brain involved in emotion and mood.