Depression can be a very serious condition that needs better treatments—especially ones that work fast and have lasting effects.
Ketamine is a drug that does both, but its use is limited because it can cause harmful side effects over time.
Scientists have been trying to understand how ketamine works so quickly and why its effects last longer than most other medications.
A new study from Northwestern Medicine has taken a big step forward in solving this mystery. The researchers found that ketamine works in two different ways: one that acts quickly and another that helps in the long run. Both ways involve new brain cells, called neurons, but they work differently.
The quick effects of ketamine come from making the new neurons that are already in the brain more active. These neurons start “firing” faster, which means they send more messages in the brain.
This helps lift a person’s mood in just a few hours. The longer-term effects of ketamine come from helping the brain grow more of these young neurons. This takes time, so the effects last longer but don’t happen right away.
Dr. John Kessler, one of the lead researchers, said this is exciting news because it could lead to new depression treatments that are both fast-acting and safe to use over time. This discovery could change how doctors treat depression in the future.
The study was led by Dr. Radhika Rawat, a medical student who used to work in Dr. Kessler’s lab. In an earlier study, she found that ketamine works fast because it makes the young neurons more active.
In this new study, she wanted to know why ketamine’s effects also last a long time. She found that ketamine increases the number of new, immature brain cells that can help improve mood in the long run.
Dr. Rawat explained it like this: Imagine these new neurons are like teenagers who are texting their friends. When ketamine makes them send more messages, the information spreads quickly—that’s the fast effect.
But ketamine also helps make more teenagers, which takes time. Once they’re ready, they can also spread more messages—that’s the long-term effect.
The study also discovered that the long-term effects are related to a specific part of the brain called the hippocampus and a chemical pathway known as BMP signaling.
Previous research had shown that many regular antidepressants also work by lowering BMP signals. This new study shows ketamine works the same way in the long run.
Dr. Rawat said this finding opens the door to new treatment ideas. For example, starting ketamine at the same time as regular antidepressants might make both work better.
This new understanding could lead to safer and more effective treatments for people struggling with depression. It shows that scientists are getting closer to developing drugs that act fast, work well over time, and don’t have the harmful side effects of ketamine.
If you care about mental health, please read studies about Cannabis use disorder linked to increased risk of these mental diseases and findings of Some mental health drugs can cause rapid weight gain.
For more about mental health, please read studies about One sleepless night can reverse depression for days and findings of Scientists find better treatment for older adults with depression.
The study is published in Cellular and Molecular Life Sciences.
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