What causes depression? Chinese and British researchers find links in the brain
Researchers say results could open up new treatment options for poor sleep and lead to a better understanding of depression
Scientists from China and Britain have discovered links in the brain between depression and sleep problems, according to a study published in an American medical journal this week.
Their findings could pave the way for new treatments for depression and insomnia, the researchers said on Friday.
“The relationship between depression and sleep has been observed for more than a century but until this study, scientists and psychiatrists knew little about how they were related,” said Feng Jianfeng, one of the study’s lead researchers and a computational neuroscience professor at the University of Warwick in Britain.
The data-driven study, by researchers at Warwick and Fudan University in Shanghai, was published in JAMA Psychiatry on Wednesday and involved analysis of data from around 10,000 people at international brain image databases, including the US Human Connectome Project and UK Biobank.
It built on work at Fudan University in 2016 by a team led by postdoctoral fellow Cheng Wei.
The team found that a part of the brain called the lateral orbitofrontal cortex, which is in charge of punishment, could make people more sensitive to negative emotions when it was overactive.
Then this year researchers from Fudan and Warwick mined brain image data of 1,017 people from the US Human Connectome Project, and compared the results with a larger data set from UK Biobank.
The results identified several brain areas strongly associated with depression and poor sleep: the dorsolateral prefrontal cortex involved in short-term memory, the precuneus in charge of the notion of self, as well as the lateral orbitofrontal cortex pinpointed in the earlier study.
Feng said these areas were at least part of the mechanism that made people dwell on bad thoughts and impaired sleep quality.
Depression has become the leading cause of illness and disability worldwide, with more than 300 million people – 4 per cent of the world’s population – living with the condition, according to the World Health Organisation (WHO). The number of people with depression grew more than 18 per cent from 2005 to 2015, the WHO said.
“So almost everyone in the world is related to these two problems: depression and poor sleep quality, either as a sufferer or a relative of a sufferer,” Feng said.
Cheng said the research opened up the possibility of new targeted treatments for people with poor quality sleep.
“Researchers at University of Toronto have already used magnetic stimulation to treat patients with depression, based on our 2016 study,” Cheng said.
The value of the study was also in how it could help researchers better understand the problem of depression, said Cheng.
“This study may also have implications for a deeper understanding of depression,” said Edmund Rolls, a neuroscientist at Warwick and another lead researcher in the study.
“This important cross-validation with participants from the USA provides support for the theory that the lateral orbitofrontal cortex is a key brain area that might be targeted in the search for treatments for depression.”
Cheng said the team at Fudan University planned to work with hospitals in China on possible treatments for depression and poor sleep quality.