A team of scientists in Hungary has identified a group of brain cells that could help regulate negative emotions.

The discovery could pave the way for more targeted treatments for mental illness.

"About 25 to 30 percent of the population will experience phobia, post-traumatic stress disorder, major depression, or anxiety disorders at least once in their lifetime," said Dr. Gábor Nyiri, lead researcher at the HUN-REN Institute of Experimental Medicine.

The team found the cells by accident while studying the brainstem. "What we discovered is this green area of the brainstem. It's quite large," Nyiri said.

These neurons appear to influence the lateral habenula – a part of the brain that helps process pain, rejection, and failure.

In people with depression, the lateral habenula can be overactive. The Hungarian team says the newly found cells appear to quiet this brain region.

These are the brain cells scientists discovered that help control negative emotions. One day, they say new treatments could target them specifically to better treat depression, PTSD, and anxiety.

Researcher Krisztián Zichó said future therapies could become more precise.

"I believe that it is possible in the near future, when we selectively target this kind of cell subpopulations – for example, through the specific receptor or some kind of other genetic mechanism – that we can cure these diseases way more effectively than today," Zichó said.

The research is still in early stages. But the implications could be wide.

More than 280 million people worldwide suffer from depression, according to the World Health Organization. Current treatments often rely on medications that affect the whole brain.

"I believe that more targeted therapies, brain region-specific therapies, will be needed in the future," Nyiri said.

For the team, the findings are just the beginning.

"If you want to do something about these kinds of diseases it is really important for society as a whole to fund this research," Nyiri said.

This small discovery in the brainstem may bring big changes for those battling mental illness.