20th October 2016
Depression's physical source discovered
Researchers have discovered the physical source of depression in the human brain, which is found to affect the lateral orbitofrontal cortex, implicated in non-reward.
Understanding of the physical root of depression has been advanced, thanks to research by the University of Warwick, UK, and Fudan University, China. The study shows that depression affects the part of the brain which is implicated in non-reward – the lateral orbitofrontal cortex – so that sufferers of the condition feel a sense of loss and disappointment associated with not receiving rewards.
This area of the brain, which becomes active when rewards are not received, is also connected with the part of the brain involved in one's sense of self, thus potentially leading to thoughts of personal loss and low self-esteem. Depression is also associated with reduced connectivity between the reward brain area in the medial orbitofrontal cortex and memory systems in the brain, which may account for sufferers having less focus on happy memories.
These new discoveries could herald a breakthrough in treating depression, by going to the root cause of the illness, and helping depressed people to stop focussing on negative thoughts.
In this particularly large study, almost 1,000 people in China had their brains scanned using a high precision MRI, which analysed the connections between the medial and lateral orbitofrontal cortex – the different parts of the human brain affected by depression. The study was carried out by Professor Edmund Rolls from Warwick, Professor Jianfeng Feng from Warwick and from Fudan University in Shanghai, Dr Wei Cheng from Fudan, and by other centres in China.
Depression is expected to overtake heart disease to become the leading global disease burden by 2030. Professor Jianfeng Feng comments on how it has become increasingly prevalent: "More than one in ten people in their lifetime 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."
"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," says Feng.
Professor Edmund Rolls looks forward to the new treatments the research could lead to: "The new findings on how depression is related to different functional connectivities of the orbitofrontal cortex have implications for treatments in the light of a recent non-reward attractor theory of depression."
The research, 'Medial reward and lateral non-reward orbitofrontal cortex circuits change in opposite directions in depression', is published in the peer-reviewed journal Brain.
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