According to the results of a meta-analysis published in JAMA Psychiatry, the symptoms of sleep disorders are observed in common areas of the brain related to executive functions and reflexes, memory, and emotion regulation. This study shows that the brain regions involved in emotion regulation and connected with the system mediating social cognition are equally dysfunctional in people with chronic sleep disorders across all etiologies.
According to this meta-analysis, while indicators of sleep disorders were found in different regions of the brain, those specifically reflecting sleep deprivation were located in the thalamus. In contrast, sleep deprivation in otherwise healthy individuals appeared as changes in the thalamus, likely reflecting an altered state of alertness. Thus, unlike sleep deprivation, sleep disorders resemble emotional disorders.
Previous research has indicated that sleep disorders have different origins but that some may overlap. Since the links between short- and long-term sleep deficiencies remain unclear, this study investigated both shared and specific neural correlates for a range of sleep-related concerns. The meta-analysis, which reviewed databases such as PubMed, Web of Science, Embase, Scopus, and BrainMap up to January 2024, identified all brain neuroimaging articles that included group differences between patients with various sleep disorders and healthy control participants, or between partially or completely sleep-deprived individuals and well-rested individuals. Out of more than 34,000 cases identified in the initial screening, 231 articles containing data from 140 unique experiments with 3,380 unique participants were included. For sleep disorders, 95 experiments with 2,302 unique participants were considered, and for sleep deprivation, 45 experiments with 1,079 unique participants were included. Transdiagnostic regional brain changes were identified across articles reporting sleep disorders and sleep deprivation.
Researchers also analyzed associated behavioral functions and connectivity patterns using BrainMap and enhanced Nathan Kline Institute-Rockland Sample datasets. In the analysis of sleep disorders, affected regions included the subgenual anterior cingulate cortex associated with reward, reasoning, and taste; and the amygdala and hippocampus associated with negative emotion processing, memory, and smell.
According to the results, in 45 experiments, the right thalamus, associated with temperature regulation and pain receptors, was consistently affected by sleep deprivation. In addition, sub-analyses on directional changes found that the subgenual anterior cingulate cortex exhibited decreased activation, connectivity, and/or volume, while clusters in the amygdala, hippocampus, and thalamus showed increased activation, connectivity, and/or volume.
Poor sleep and sleep disorders are risk factors for various mental health problems and are frequently reported by patients with a wide range of neuropsychiatric disorders, making them a general concern.