Ketamine, an illegal club drug, could hold out hope for those suffering from depression.
Recent studies have found that it can lift depression in as little as 40 minutes and treat people for a week or longer.
Ketamine for depression was administered to people with bipolar disorder, one of the most serious mental health problems.
The fact that ketamine works so quickly, and on one of the most resistant forms of depression, has many researchers fascinated.
Traditional antidepressants can be slow to work — if they work at all.
Ketamine — sometimes known as a ‘horse tranquiliser’ — is not a new drug, although its use for those with depression is relatively new.
Along with its use in veterinary medicine, it is also a club drug, known as ‘Special K’.
The problem with using ketamine as a treatment for depression is that it gives people an addictive high.
Ketamine for depression
Now, new research has provided a critical insight into how ketamine works — and possibly a way to side-step its addictive properties.
Scientists at the National Institutes of Health (NIH) have found that it is not the ketamine itself that causes the antidepressant effect.
Instead, it is another substance into which ketamine is broken down by the body that provides the effect (a metabolite).
Dr Carlos Zarate, one of the study’s co-authors, said:
“This discovery fundamentally changes our understanding of how this rapid antidepressant mechanism works and holds promise for development of more robust and safer treatments.
By using a team approach, researchers were able to reverse-engineer ketamine’s workings from the clinic to the lab to pinpoint what makes it so unique.”
Although previous research has been carried out on humans, the new study tested ketamine for depression in mice.
It found that the mechanism of action was not what many had assumed.
Instead it works through a glutamate receptor: α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)
With this information the scientists were able to make an antidepressant which worked on the mice without the side-effects.
Dr Todd Gould, one of the study’s authors, said:
“Now that we know that ketamine’s antidepressant actions in mice are due to a metabolite, not ketamine itself, the next steps are to confirm that it works similarly in humans, and determine if it can lead to improved therapeutics for patients.”
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The study was published in the journal Nature (Zanos et al., 2016).