Does Ketamine Act Like an Opioid? Understanding the New Research

On August 29th, The American Journal of Psychiatry published a research study out of Stanford University that aimed to explain the relationship between ketamine and the opioid pathway in the brain. Low-dose ketamine has been known to alleviate depressive symptoms for years, but researchers aren’t sure exactly how it works to ease depression. The main theory is that ketamine affects the glutamate system, which has implications in memory and learning – basically, ketamine ‘reboots’ the brain by promoting the growth of new neuronal connections. Ketamine for the treatment of depression has become increasingly mainstream due to its rapid and robust effect on depressive symptoms and suicidal ideation – while traditional antidepressants (such as SSRIs) take 4-6 weeks to have a full effect, a single ketamine infusion has been shown to create a positive response in mood and depression in as little as an hour, and can last as long as 2 weeks.

Researchers at Stanford are now saying that it may be opioid pathway involvement that causes the rapid antidepressant effects, while the glutamate system is what makes the symptom relief last for weeks. This small study involved two ways to treat depression – the first was by giving patients an IV infusion of ketamine alone. The second was by first giving patients naltrexone, which blocks the effects of opioids, followed by an IV infusion of ketamine at the same dose as the first group. The results were dramatic – the group who got ketamine alone felt significant relief of their depressive symptoms (over 50%), while the group who got naltrexone first felt virtually no relief. These results seem to suggest that opiate receptors are affected by ketamine. One of the study’s authors, Carolyn Rodriguez, said that the results of this study are “the beginning of a conversation” and said it “highlights that ketamine’s mechanism of action is complicated.”

Although this study needs to be replicated with a much larger cohort of patients, these results suggest that ketamine may act through a number of important neurotransmitter systems that affect mood, anxiety, and the sense of well-being. This is an exciting time in the neurobiological research of depression. Ketamine promises to not just to be an effective treatment in itself, but to give us invaluable insights into the underlying neurobiology of depression.

At Principium Psychiatry, we offer IV Ketamine infusions for depression in NYC. Our private office in Manhattan provides a getaway where exceptional, state of the art treatment is combined with the art of medicine in a secluded office off Central Park. In addition to Ketamine, Principium Psychiatry offers TMS for depression in NYC. We are affiliated with Weill Cornell Medicine, Columbia University, and New York Presbyterian Hospital. Please contact our main office at 212-335-0236 for further information.

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