The Ketamine is an anaesthetic drug used as a sedative in the world of medicine. In addition, it is often illegally marketed as a recreational drug with hallucinogenic potential, whose consumption in large quantities can cause severe damage, including death from overdose.

Recently, a study by the Karolinska Institute in Sweden revealed that ketamine, in small doses, can be used for the treatment of severe depression, that is, those that do not improve through therapy or other conventional treatments.

From tests with a sample of 30 people suffering from this type of depression, also known as persistent depression or dysthymia, doctors discovered a link between the anaesthetic drug and serotonin, a neurotransmitter whose deficiency is linked to depression.

For this, a positron emission tomography (PET) imaging technique was used, which allows us to observe the neuronal interaction with the substance. In the first part, 20 participants were given ketamine and 10 a placebo made from saline.

A double-blind method was used, in which the doses were given randomly so that neither the participants nor the doctors knew which patients had ingested the drug. Brain images of each participant were taken before the infusions and between 24 and 72 hours after.

In the next phase, those who agreed — 29 out of 30 participants — received ketamine twice weekly for 14 days. The results were overwhelming: more than 70% of the treatment participants obtained improvements measured through a rating scale for depression.

There are 14 different types of receptors on each neuron for this neurotransmitter. The study focused on one of them, the serotonin receptor 1B, for whose identification the PET chamber was programmed.

The researchers found that ketamine acts directly on this receptor, and while it reduces the release of serotonin, it increases that of another neurotransmitter called dopamine, linked to feelings of satisfaction and reward in the brain.

It is the first time that a study does prove that the ketamine treatment increases the amount of serotonin 1B receptor, as said one of the authors of the study, the head of the Department of Clinical Neuroscience Johan Lundberg, in a statement. However, caution is required to draw conclusions about the results, he clarified.

“Ketamine has the advantage of being very rapid-acting, but at the same time it is a narcotic-classed drug that can lead to addiction.,” he said. Still, the research results may provide input to “examine in future studies if this receptor can be a target for new, effective drugs that don’t have the adverse effects of ketamine” he concluded.