LONDON – An international research team of scientists in England says they have identified the physical source of depression in the brain in a new study.

Investigators traced depression, one of the most common mental ailments in the world, to the lateral orbitofrontal cortex, the part of the brain responsible for a non-reward mechanism, the UPI reported on Wednesday.

According to the research team, this is likely the reason people living with depression often feel a sense of loss, disappointment and low self-esteem.

In addition to the lateral orbitofrontal cortex, researchers also linked depression to the medial orbitofrontal cortex and memory systems, which they say explains why individuals with depression have difficulty accounting for happy memories.

The research team was comprised of investigators from the University of Warwick in England and Fudan University in China. Their findings were published in the journal Brain.

“More than one in ten people in their life time suffer from depression, a disease which is so common in modern society and we can even find the remains of Prozac (a depression drug) in the tap water in London,” Professor Jianfeng Feng said in a press release.

During the study, the team analyzed brain scans for almost 1,000 people in China using high-precision MRI. By using this technique, they were able to observe changes in the connections between the medial and lateral orbitofrontal cortex.

The authors hope finding the physical root of depression will help develop more advanced treatments.