Adults with depression show a shutdown in the production of new neurons in the hippocampus, a brain region critical for memory and emotion, according to a new study from Columbia University. This discovery not only deepens our understanding of depression but also points to potential new avenues for treatment.
The Research
Researchers led by Dr. Maura Dupont, professor of psychiatry at Columbia University Vagelos College of Physicians and Surgeons, analyzed nearly half a million brain cells from deceased adults with and without depression. They found that in those with major depressive disorder, the process of neurogenesis—the creation of new neurons—was significantly disrupted. This is one of the first studies to show such a link in human brains.
The team also identified broad molecular changes beyond neurogenesis. The affected genes included those involved in forming new connections between neurons, supporting communication among brain cells, supplying cellular energy, and intracellular transport. The hippocampus's primary circuit for forming new emotional memories, the trisynaptic circuit, showed signs of inflammation and cellular stress.
"Historically, depression was thought to be a disease of neurotransmitter deficiency, especially serotonin," says Dr. Dupont, "but we now think that depression stems from multiple issues that affect our neurons' ability to adapt to stress and changing environments. Without the ability to create new neurons, people may lack the resilience to effectively adapt."
The study was published in the journal Science on August 25, 2026, and is the first to provide direct evidence that neurogenesis stalls in depressed adults.
Why It Matters
The hippocampus plays a key role in a function called pattern separation—the ability to distinguish between similar memories and keep the emotional tone of past events separate from current ones. When neurogenesis is impaired, this ability weakens. As a result, new experiences can become tainted by old, painful memories, leading to a negative bias in interpreting events.
Dr. Dupont explains: "If you're out with a friend who is quiet, with intact pattern separation you see this as a unique event. With impaired pattern separation, it mixes with past feelings of rejection, and you assume they're upset with you." This cognitive distortion is common in depression.
These findings could lead to new treatments that specifically target the molecular pathways controlling neurogenesis, offering hope for people who don't respond to current antidepressants.
What You Can Do
While this research is about depression, it highlights the importance of a healthy hippocampus for everyone. Lifestyle factors that support brain health—like regular aerobic exercise, adequate sleep, and a balanced diet rich in omega-3 fatty acids—are known to promote neurogenesis in animals. Integrating these habits into your life can help maintain cognitive flexibility and emotional resilience.
If you're interested in how your own memory and pattern separation are working, consider testing your cognitive skills with a free IQ test or brain training exercises that challenge your memory and mental agility.
Source: ScienceDaily Mind & Brain
Curious about your own brain? Take our free adaptive IQ test or try 306 brain training levels.