Increased functional connectivity between certain brain regions provides a neural basis for linking depression with poor sleep quality, a new study by researchers at the University of Warwick (UK) and Fudan University (China) reports. The research could lead to better sleep quality for people with depression, and opens up the possibility of new targeted treatments.
Analysing data from around 10,000 people, Professor Jianfeng Feng and Professor Edmund Rolls from Warwick’s Department of Computer Science, with Dr. Wei Cheng from Fudan University, examined the neural mechanisms underlying the relation between depression and quality of sleep.
In the brains of those living with depressive problems, they discovered a strong connection between the dorsolateral prefrontal cortex (associated with short-term memory), the precuneus (associated with the self) and the lateral orbitofrontal cortex (associated with negative emotion).
Increased Functional Connectivity
This analysis of data from the Human Connectome Project showed that these functional connectivities underlie the relation between depressive problems and sleep quality. The researchers conclude that increased functional connectivity between these brain regions provides a neural basis for how depression is related to poor sleep quality.
“The understanding that we develop here is consistent with areas of the brain involved in short-term memory (the dorsolateral prefrontal cortex), the self (precuneus), and negative emotion (the lateral orbitofrontal cortex) being highly connected in depression, and that this results in increased ruminating thoughts which are at least part of the mechanism that impairs sleep quality,"
Professor Jianfeng Feng, from the University of Warwick’s Department of Computer Science, said.
“This study may also have implications for a deeper understanding of depression. 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,"
Professor Edmund Rolls commented.
Public Health Implications
These findings, Professor Jianfeng Feng said, could have important public health implications, as both sleep problems and depression affect a large number of people. He commented:
“In today’s world, poor sleep and sleep deprivation have become 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. The disorder of insomnia has become the second most prevalent mental disorder. And major depressive disorder is also ranked by the World Health Organization as the leading cause of years-of-life lived with disability. According to a recent statistic, it affects approximately 216 million people (3% of the world’s population). So almost everyone in the world is related to these two problems, as a sufferer or a relative of a sufferer."
Depression and sleep problems often go hand-in-hand. About 75% of depressed patients report significant levels of sleep disturbance, such as difficulty of falling asleep and short duration of sleep (insomnia). People with insomnia also have a higher risk of developing depression and anxiety than those who sleep normally.
There were some limitations to the study. The authors note that the depressive score, the Adult Self-report DSM-IV Depressive Problems raw score, based on the Achenbach Adult Self-report for Ages 18-59, was used as an indicator of depressive symptoms, rather than a formal diagnosis. Additionally, the strong correlation found between depression and poor sleep, does not indicate causal directionality, which could be in both directions.
Support for the work came from the Shanghai Science & Technology Innovation Plan, the National Natural Science Foundation of China, the Shanghai AI Platform for Diagnosis and Treatment of Brain Diseases, Base for Introducing Talents of Discipline to Universities, the Shanghai Sailing Program, the Research Fund for the Doctoral Program of Higher Education of China, and Natural Science Foundation of Shanghai.
Cheng W, Rolls ET, Ruan H, Feng J Functional Connectivities in the Brain That Mediate the Association Between Depressive Problems and Sleep Quality JAMA Psychiatry doi:10.1001/jamapsychiatry.2018.1941
Image: Dr Jonathan Clarke. CC BY