Summary: A new study shows that ketamine helps people with depression quickly update their beliefs, thus having fewer negative views. Hence, those treated with ketamine become more receptive to positive experiences.
Depression is among the most common mental health disorders. There are tens of antidepressants used to manage the condition. However, antidepressants fail to help in one-third of cases, thus called treatment-resistant depression (TRD). Ketamine may help in TRD. Moreover, it acts quickly. Though ketamine is still not approved for depression treatment, more and more clinics in the US are now using ketamine to treat depression due to its excellent and brisk effect in many instances. Thus, researchers at CNRS, Sorbonne University, and clinicians from the AP-HP and at Paris Brain Institute decided to explore how it works in depression. The same questions matter for post-traumatic stress disorder treatment. Ketamine is an approved anesthetic. It may also help manage pain. It is also a popular drug of abuse. However, its use as an antidepressant has been rising in recent years. It is especially good for resistant cases. Studies show that ketamine increases the ability to overcome negative beliefs leading to severe depression. The results of this study were recently published in the journal JAMA Psychiatry. Depression is among the most common psychiatric conditions. CDC data shows that about 4.7% of adults in the US are living with the condition. It results in almost 45,000 suicides each year. People living with depression feel sad most of the time. They stop experiencing pleasure from living. In many cases, they lose interest in life. They often have very pessimistic views about life and constantly live in fear. Negative beliefs are among the most significant problems in these people. In recent years, tens of new drugs have been introduced to manage depression. However, medications do not appear to work in about one-third of cases. These are people living with treatment-resistant depression (TRD). Hence, it is essential to find effective remedies for these people. Fortunately, ketamine appears to be effective in many cases of resistant depression. Moreover, ketamine is a well-known drug that has been in clinical use for more than half a century. What is incredible about ketamine is that it acts fast. Unlike most commonly used antidepressants that need weeks to start acting, ketamine starts working within a few hours. Therefore, to understand how ketamine works in depression, doctors enrolled 26 patients with resistant depression and 30 healthy adults in a study. In the study, researchers asked all the participants to estimate the probability of 40 negative events happening in their life, like losing their wallet, getting cancer, or having a car accident. After the response, researchers told the participants the true probability of those events occurring in their life. The research team wanted to update the beliefs of the participants by providing factual information. They found that after receiving the facts, healthy adults could quickly update their beliefs, but those living with depression had difficulty in doing so. After the initial assessment, they treated 26 patients living with TRD by giving ketamine infusion thrice a week. They again repeated the above test after about four hours of ketamine administration. Again, they found that ketamine significantly improved their ability to update their beliefs. Thus, they became less sensitive to negative information, resulting in improved mental health. Simply said, ketamine enhanced the belief updating capacity of TRD patients. Therefore, researchers concluded that ketamine significantly improves the belief updating capacity of those living with TRD, thus resulting in reduced depression over time.
Ketamine is also used in chronic pain. Our ketamine therapy page sets out the separate evidence base for pain, which does not carry over from the depression literature.
Frequently asked questions
How fast does ketamine work for depression?
Within hours. Most common antidepressants need weeks before they start acting. In the Paris Brain Institute study, patients with treatment-resistant depression were retested about four hours after a ketamine infusion, and their ability to update negative beliefs had already improved significantly. That speed is the main reason more clinics in the US now use ketamine for resistant cases.
How does ketamine change negative thinking in depression?
It helps people revise their beliefs when they get new facts. Participants guessed their odds of 40 bad events, such as losing a wallet or getting cancer, then heard the true odds. Healthy adults adjusted quickly; people with depression struggled to. After ketamine, depressed patients updated their beliefs far better, became less sensitive to negative information, and grew more receptive to positive experiences.
What is treatment-resistant depression?
It is depression that does not respond to standard antidepressants. Even with dozens of medications available, drugs fail in about one-third of people with depression. These patients feel sad most of the time, stop enjoying life, and often hold deeply pessimistic beliefs. Ketamine, a drug in clinical use for more than half a century, works in many of these resistant cases.
Is ketamine also used for chronic pain?
Yes. Ketamine is an approved anesthetic and it also helps manage pain. The evidence for pain is separate from the depression research, so results from depression studies do not automatically apply to pain. Our ketamine therapy page explains how we use it for pain.
Dr. Gurpreet Singh Padda, MD, MBA, MHP
