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Shared neural mechanisms underlie link between depression, sleep

Analysis revealed that both poor sleep quality and depressive problems correlated to functional connectivities involving the lateral orbitofrontal cortex, the dorsolateral prefrontal cortex, the cingulate cortex and the precuneus in the brain.

Further, the connectivity links between these brain areas provided a neural basis for the relationship between depression and poor sleep quality, according to study findings.

“The widespread use of the [Pittsburgh Sleep Quality Index] has shown that subjective sleep disturbances are associated with depression. Moreover, there is a genetic component to the association between poor sleep quality and depression, and this makes it especially interesting to search for possible neural mechanisms that may mediate the association,” Wei Cheng, PhD, of the Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, China, and colleagues wrote. “Advances in our understanding of the neural bases of depression, and how they may be associated with poor sleep quality, are key areas for investigation.”

To determine the brain areas that mediate the link between depressive symptoms and poor sleep quality, researchers examined data from 1,017 participants in the Human Connectome Project on self-reported depressive problems via scores on the Adult Self-Report of Depressive Problems, sleep quality via survey and resting-state functional MRI. The investigators also conducted a cross-validation of the sleep findings in 8,718 participants from the UK Biobank.

In total, 1,017 participants from the Human Connectome Project drawn from a general population in the U.S. were included in this study. Cheng and colleagues found that depressive problems score positively correlated with poor sleep quality (P < .001).

The study identified 162 functional connectivity associations involving areas tied to sleep, including the precuneus, anterior cingulate cortex and the lateral orbitofrontal cortex. Of these connections, 39 were also tied to depressive problems scores. Specifically, the brain areas with increased functional connectivity linked with sleep and depressive issues included: the lateral orbitofrontal cortex, dorsolateral prefrontal cortex, anterior and posterior cingulate cortices, insula, parahippocampal gyrus, hippocampus, amygdala, temporal cortex, and precuneus, according to the investigators.

Moreover, results from a mediation analysis revealed that these functional connectivities underlie the connection between depressive problems score and poor sleep quality (P < .001).

“This is the first study, to our knowledge, to examine the neural mechanisms underlying the association of depression with sleep, a topic of great interest, with a large sample,” Cheng and colleagues wrote. “The understanding that we developed in this study 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, which results in increased ruminating thoughts that are at least part of the mechanism that impairs sleep quality.” – by Savannah Demko

Disclosure: The authors report no relevant financial disclosures.