10/24/2026
🧠 Ketamine can lift depression within hours, much faster than standard antidepressants. A study in mice suggests why: it acts first on one small brain region linked to bad moods.
Most antidepressants take weeks to work. That delay can be dangerous for people with severe depression.
Low doses of ketamine can ease symptoms in hours, but scientists have debated exactly where in the brain it starts working.
Researchers at Zhejiang University in China studied this in mice showing depression-like behavior.
They focused on the lateral habenula, a tiny region deep in the brain. It is sometimes called the brain's "anti-reward center," because it becomes overactive in depression.
After the mice were given ketamine, activity in the lateral habenula dropped sharply within minutes to a couple of hours.
Other areas linked to mood, like the hippocampus, showed little change in that early window.
The team found three reasons this region responds first. Its cells are very active, ketamine blocks active cells more easily, and these cells have fewer spare receptors to compensate.
When the researchers removed ketamine's target receptor only in this region, its fast antidepressant effect disappeared.
Later changes in other brain areas also failed to happen. This suggests the lateral habenula is where ketamine's effect begins.
"The first brain region to respond signifies a more direct interaction with ketamine," said senior author Hu Hailan.
But there are important caveats. This research was done mainly in mice, and depression in animals is very different from depression in people.
Ketamine for depression should only be used under medical supervision. It can have side effects and be misused.
If you are struggling with depression, please talk to a doctor or mental health professional.
📃 RESEARCH PAPER
📌 Min Chen et al., "Brain region-specific action of ketamine as a rapid antidepressant," Science (2024).
