July 25 (UPI) -- Researchers have found a neural link between depression and sleeplessness, findings they believe could lead to new targeted treatments for the conditions.
Brain regions associated with short-term memory, self and negative emotions can lead people down a hole of misery and depression, leading to bad sleep quality, according to researchers at the University of Warwick in England. The findings were published Wednesday in the Journal of the American Medical Society's Psychiatry.
Depression and sleep problems have previously been closely associated. About 75 percent of depression sufferers reported insomnia in a 2008 study by researchers at the University of Bristol.
With depression and sleeplessness "almost everyone in the world is related to these two problems, as a sufferer or a relative of a sufferer," Dr. Jianfeng Feng, a researcher in Warwick's Department of Computer Science, said in a press release.
"In today's world, poor sleep and sleep deprivation have become a common problem affecting more than a third of the world's population due to the longer work hours and commuting times, later night activity and increased dependency on electronics," Feng said.
The National Sleep Foundation reports that forty-five percent of Americans' sleep problems affected their daily activities at least once a week in their inaugural Sleep Health Index, and the World Health Organization says about 3 percent of the world's population has a major depressive disorder.
Researchers analyzed data on 1,017 participants between the ages of 22 and 35 who participated in the Human Connectome Project at the Washington University-University of Minnesota Consortium in 2017. Researchers obtained the participants' sleep and depression scores.
Of those participating in the project, researchers found that about 9 percent of the participants were diagnosed with a major depressive episode.
Among those with depression, researchers found a strong connection between the dorsolateral prefrontal cortex, which is associated with short-term memory; the precuneus, which is associated with the self, and the lateral orbitofrontal cortex, which is associated with negative emotion.
Researchers believe it is the first time the neural mechanisms underlying the association of depression and sleep have been studied in a large sample.
"The relation between depression and sleep has been observed more than 100 years, and now we have identified the neural mechanisms of how they are connected for the first time," Feng said. "These findings provide a neural basis for understanding how depression relates to poor sleep quality, and this in turn has implications for treatment of depression and improvement of sleep quality because of the brain areas identified."
Edmund Rolls, also a professor in the computer sciences department, said the lateral orbitofrontal cortex that might be targeted in the search for treatments for depression.
"This study may also have implications for a deeper understanding of depression," he said.