The root cause of depression has historically been tricky to pinpoint, but researchers at the University of Warwick in the U.K. and Fudan University in China may have found it. MR imaging revealed that depression affects the lateral orbitofrontal cortex, which is the part of the brain that’s associated with non-reward.

An estimated 350 million people globally suffer from depression, according to the World Health Organization, and this discovery may represent a major breakthrough in treating the root cause of the disorder and helping patients to stop focusing on negative thoughts.

The researchers conducted MR scans on 1,000 people in China to evaluate the connections between the medial and lateral orbitofrontal cortex.
They found that the region of the brain that’s active when rewards aren’t received is also connected with the part of the brain associated with one’s sense of self. That means that when a person with depression doesn’t receive a reward, it can lead to low self-esteem and thoughts revolving around personal loss.

The research also discovered that depression is linked to less connectivity between the reward part of the brain in the medial orbitofrontal cortex and memory systems in the brain, which may explain why those with depression don’t focus on happy memories.

"Our finding, with the combination of big data we collected around the world and our novel methods, enables us to locate the roots of depression, which should open up new avenues for better therapeutic treatments in the near future for this horrible disease," Jianfeng Feng, professor at Warwick and Fudan University, said in a statement.

This is not the first study that used MR imaging to assess patients with depression. A University College, London study that was published in late May conducted fMRI on depressed patients and found that the region of the brain that responds to bad experiences has the opposite reaction to expectations of aversive events compared to health adults.

Another study published in Biological Psychiatry in February suggested that a brain reward center called the striatum may be directly affected by inflammation, which increases the risk for depression. The findings demonstrate that an MR technique can be used to measure the effects of inflammation on the brain.

“This technique could be a powerful way to identify patients who are most sensitive to effects of inflammation on the brain. It could also be used to monitor response to novel anti-inflammatory therapies that are now being tested in depression,” Dr. Neil Harrison, the lead researcher and head of the psychoneuroimmunology lab at Brighton & Sussex Medical School, said in a statement.

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