Ketamine showed remarkable results when used in low doses for patients diagnosed with severe depression. The drug was formerly used as an anaesthetic.
The scientists at Karolinska Institutet spotted the action of ketamine and published the novel outcomes in Translational Psychiatry. The ketamine sensitive spots are specific serotonin receptors located in the brain. They hope to create an effective treatment for hard-to-treat depression that is rapid-acting and risk-free.
The Highest Rate of Depression Recorded In History
Depression is one of the most common disorders of the century. In Sweden, the rate of depression is one in five for women and one in ten for men. Also, between 15 and 30 percent of the patients report no improvement after two attempts of therapy. The last reports showed that a low-dose administration of the anesthetic drug is a fast tool for some of the patients, but how it does its magic remains unknown. However, it was designed a ketamine nasal spray that received approval both in the USA and EU.
What Makes Ketamine so Effective?
To get a clear insight into how ketamine works, a group of researchers at Karolinska Institutet in Sweden imaged the brains of the volunteers using a PET (positron emission tomography) camera. The study’s first author Mikael Tiger, a researcher at the Department of Clinical Neuroscience, Karolinska Institutet added:
In this, the largest PET study of its kind in the world, we wanted to look at not only the magnitude of the effect but also if ketamine acts via serotonin 1B receptors. We and another research team were previously able to show a low density of serotonin 1B receptors in the brains of people with depression.
The Ultimate Test
The first step was to place 30 patients diagnosed with difficult-to-treat depression into two groups: a ketamine-infusion group (20 patients) and a placebo group. Neither the patients nor doctors knew which is where and who will get the active substance. The volunteers’ brains were imaged with the PET camera before and after the experiment.
The second step was to administer ketamine twice a week for two weeks to 29 individuals who agreed to. It concluded that more than 70 percent of those who took ketamine showed a visible improvement, measured with a depression rating scale. Serotonin is the main link to our happiness and when below normal levels it leads to depression or other severe conditions.
The Scientific Explanation Behind
Neurons possess 14 different types of receptors for ketamine. Inside the study, scientists used a radioactive marker that adheres to serotonin 1B receptors.
The scientists noticed that ketamine works through these receptors in unpreceded ways. Adhering to these receptors, it decreases the quantity of serotonin and maximizes the dopamine, a neurotransmitter that is responsible for the rewarding feelings. The latter makes people feel good about their life, something that is missing within depression.
Johan Lundberg, research group leader at the Department of Clinical Neuroscience, Karolinska Institutet stated that ketamine has numerous advantages, amongst which is the rapid-acting effect. Although, being a narcotic-classed drug that can drive an addiction, the researchers are looking for safer options. However, the study managed to display how ketamine was able to multiply the serotonin 1B receptors and this is a huge breakthrough for the medical world.
The study was carried out in association with North Stockholm Psychiatry and was sponsored by the Swedish Research Council, the Söderström König Foundation, the Centre for Psychiatry Research, Region Stockholm, the Swedish Psychiatric Foundation and Karolinska Institutet.
Publication: “A randomized placebo controlled PET study of ketamine’s effect on serotonin 1B receptor binding in patients with SSRI resistant depression.” Mikael Tiger, Emma R. Veldman, Carl-Johan Ekman, Christer Halldin, Per Svenningsson and Johan Lundberg.Translational Psychiatry, online 1 June 2020, doi: 10.1038/s41398-020-0844-4.