Our brains are constantly creating beliefs – about ourselves, about the world, about the future. They help us navigate reality. But with depression, this mechanism malfunctions: negative thoughts become entrenched, and it seems impossible to change them.
What if there was a way to restart this process?
Ketamine – a rapid mood switcher
Conventional antidepressants are slow-acting, taking weeks to show effects. Ketamine, which was previously used as an anesthetic, works in a completely different way. It acts on NMDA receptors and can significantly alter a person's mental state within hours of administration.
Patients with severe depression that had not responded to other treatments often described this effect as a “change of perspective.” Negative beliefs that had seemed unchanged for months or years suddenly lost their power. Some even said that their thoughts no longer seemed “theirs.”
Depression as a trap of negative beliefs
According to WHO estimates, more than 280 million people worldwide suffer from depression, and 700,000 lose their lives to suicide each year. One of the most dangerous symptoms is the belief that things will never change, that you are worthless or doomed to fail.
These thoughts work in a feedback loop: if a person feels that they are not accepted in society, they begin to avoid others. This, in turn, further increases the feeling of isolation. This creates a vicious cycle that is difficult to break.
What did the research show?
Scientists conducted an experiment: they asked depressed patients to estimate the likelihood of negative events in their lives (such as an accident or a dog attack). They were then informed of the actual statistical risks and given the opportunity to revise their estimate.
In healthy people, it works simply: they easily accept positive news and adjust their beliefs. But people with depression remained “deaf” to the good news, continuing to believe the worst.
But here's what happened after the ketamine injection: Within four hours, the patients were responding to positive information in the same way as healthy people. Their brains became more flexible, and they learned to update their beliefs again.
What's next?
Scientists are still studying exactly how ketamine changes brain function, but it is believed that it helps restore the balance between neural processes responsible for predicting the future and emotional plasticity.
These findings could radically change the approach to treating depression. Ketamine does not just relieve symptoms, but rather “resets” the way we think. This gives hope for new therapies that combine pharmacology with psychotherapy.
Similar studies are already underway with other psychedelics, such as psilocybin. Could the future of psychiatry lie in the ability to change our beliefs in the same way we change our thoughts?
Perhaps the answer is closer than we think.
According to the study “Evaluating the Early Effects of Ketamine on Belief Renewal Bias in Patients with Treatment-Resistant Depression,” which was recently published in the journal JAMA Psychiatry .
