Researchers Uncover Neural Link Between Poor Sleep Quality, Depression

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Psychological research has long held that depression may lead to diminished sleep quality. Meanwhile, sleep research suggests low-quality sleep may provoke or exacerbate depression. Now, a new study sheds some light on precisely why poor sleep quality and depression may be so closely linked.

The study, which was published in JAMA Psychology, suggests that poor sleep quality and depression may share certain neural connections within the brain.

“We found that brain areas with connectivity related to sleep quality also had correlations with depression,” study co-author Dr. Edmund Rolls, professor of computer science at the University of Warwick in Coventry, England, told Mattress Clarity via email.

In addition to suggesting that poor sleep quality may cause depression, Rolls says the research also suggests the relationship may go both ways. “Some effects were found both way round, though the effects in the direction that depression causes poor sleep quality were less strong,” he says.

The study’s authors posit that these findings have important implications both for the treatment of depression and the field of sleep research.

[Editor’s Note: The content provided on this site is for general informational purposes only. Any information provided is not a substitute for professional medical advice. We encourage everyone to consult with the appropriate health expert if they have concerns.]

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Identifying Links Between Depression And Poor Sleep Quality

The study concerned itself with one central question: Do certain connections within the brain help explain the association between depressive symptoms and poor sleep quality?

To answer their question, the researchers reviewed data from 1,107 participants in the Human Connectome Project, which compiles massive amounts of neural data. These participants ranged in age from 22 to 35 years. Participants were part of the general U.S. population and were not selected for having issues with depression.

The data included information about self-reported depressive problems, self-reported sleep quality measurements, and resting-state functional magnetic resonance imaging (fMRI) measurements (fMRI involves measuring and mapping brain activity). The sleep findings were cross-validated using data drawn from 8,718 participants in the UK Biobank.

The researchers found that depressive problems were correlated with poor sleep quality. Furthermore, they discovered that several brain areas were associated with both sleep and self-reported depressive problems. These brain areas include the hippocampus, the amygdala, the temporal cortex, and several other neural regions.

In total, sleep and depressive problems shared 39 functional connectivity links in the brain. “Functional connectivity is measured by the correlation between the BOLD fMRI signal in two brain areas,” explains Rolls. “A high functional connectivity implies that two areas are influencing each other, or are both influenced by a common input.”

The researchers’ analysis suggests these neural links help explain the association between depressive issues and poor sleep quality.

RELATED: How Sleep Plays A Role In Seasonal Affective Disorder

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Implications For Depression And Sleep

Uncovering a neurological basis for the relationship between poor sleep quality and depression may have several important implications, says Rolls.

“This very large-scale study did identify brain regions and their connectivity [as it relates] to sleep quality,” he says. “These findings are likely to be very robust because of the large numbers of participants and the cross-validation.”

In other words, these findings may enable sleep researchers to better understand the cognitive basis of sleep quality.

Additionally, Rolls says this research may facilitate advancements in the treatment of depression. “Understanding the brain systems better that are involved in depression provides new insight into possible treatments,” he says.

Before those treatments are determined, more research is still needed. The researchers don’t yet know exactly how poor sleep quality provokes depression and depression impairs sleep quality. But now that they’ve identified the neural connections at work, they’re perhaps one step closer to finding out.

[Editor’s Note: The content provided on this site is for general informational purposes only. Any information provided is not a substitute for professional medical advice. We encourage everyone to consult with the appropriate health expert if they have concerns.]

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Laura Newcomer

Laura Newcomer is the Editorial Controller at Mattress Clarity, where she occasionally writes sleep news. She's worked as a professional writer and editor for over a decade and has been published in or on outlets such as TIME, Washington Post, Inc., Entrepreneur, Huffington Post, Women's Health, and many more. Her primary areas of interest include sleep, fitness, nutrition, eco-friendly living, education, and all things wellness.