Состав микробиома кишечника позволяет отличить депрессию у пожилых от формы с сопутствующим расстройством поведения во сне

The composition of the gut microbiome can distinguish between older adults with major depressive disorder (MDD) and older adults with MDD and comorbid rapid eye movement (REM) sleep behavior disorder (RBD). These findings were published in Molecular Psychiatry. Patients with MDD frequently report symptoms of RBD, with 40% of patients having probable RBD and nearly 9% having RBD. Patients with comorbid MDD and RBD have early neurodegenerative markers, suggesting it may be a distinct depression subtype. Researchers from the Chinese University of Hong Kong conducted this case-control study to examine whether MDD with RBD would contribute to neurodegenerative risk and evaluated whether the gut microbiome could help discriminate between MDD and RBD from MDD without RBD features. Eligible study participants were aged 40 years and older and were recruited at a sleep and psychiatry center between 2018 and 2024. All study participants underwent a clinical assessment that collected sociodemographic data and provided a stool sample. A validation dataset was included using 2 external cohorts with patients with MDD and RBD or MDD who were recruited between 2023 and 2025 and those who were recruited between 2024 and 2025. The gut microbiome was assessed by metagenomics and compared between cohorts. Additionally, researchers measured iRBD-related dysbiosis, which was defined by a dysbiosis score. These findings support a stratified framework for older adults with [major depressive disorder], in which comorbid [REM behavior disorder] may delineate a subgroup with potential neurodegenerative risk. To measure anxiety and depression symptom severity, researchers used the Hospital Anxiety and Depression Scale (HADS). To assess motor symptoms and cognitive function, researchers used the Unified Parkinson’s Disease Rating Scale (UPDRS) and the Hong Kong version of the Montreal Cognitive Assessment (HK-MoCA). To define medication usage, drug intake during the stool collection period was documented in electronic medical records. Researchers also used the MINI International Neuropsychiatric Interview for the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-4) or the Structured Clinical Interview for DSM-5 to assess psychiatric disorders. A total of 420 study participants were included for final analysis. Study participants were then separated into a 4-group design: those with MDD and RBD (n=82; mean age, 66.2 years; 62.2% men), those with MDD only (n=80; mean age, 65.6 years; 50.0% men), those with idiopathic/isolated REM behavior disorder (iRBD; n=134; mean age, 67.9 years; 78.4% men), and control cohorts comprised (n=124; mean age, 65.5 years; 61.3% men). Participants from those with MDD and RBD, those with MDD only, those with iRBD, and control individuals had HADS depression scores of 7.0, 7.0, 4.4, and 3.7 (P <.001), respectively. At the clinical examination, functional constipation and constipation-related symptoms were most prevalent in MDD and RBD (28.0%) and iRBD (33.6%), while irritable bowel syndrome (IBS) and loose or watery stools were most prevalent in those with MDD only. Researchers also noted that those with MDD and RBD had more loose or watery stools than those with iRBD. Both MDD and RBD and iRBD groups exhibited a neurodegenerative profile, which included increased total likelihood ratio of prodromal Parkinson disease, higher UPDRS part 3 motor score, and olfactory deficits. Those with iRBD vs control individuals had a higher number of differentially abundant species in the stool samples (n=89), followed by MDD and RBD (n=49), and MDD (n=15). Only 1 species in the Ruminococcaceae family (GGB58485 SGB80143) was consistently depleted in all 3 groups relative to control individuals. Researchers noted that a total of 37 microbial species were altered in both MDD and RBD and iRBD cohorts. Those with MDD and RBD vs control individuals had the highest number of differentially abundant microbial metabolic pathways in the stool samples (n=49), followed by iRBD (n=44), and MDD (n=26). A total of 6 pathways were shared among patients relative to control individuals. A total of 13 pathways were shared between MDD and RBD and iRBD cohorts, whereas only 4 were shared between MDD only and those with MDD and RBD. A Recursive Feature Elimination (RFE) analysis distinguished MDD and RBD from control individuals with an area under the curve (AUC) of 0.73 (95% CI, 0.69-0.76), and a microbiome-based classifier distinguished MDD and RBD from MDD only with an AUC of 0.73 (accuracy, 0.68; sensitivity, 0.73; specificity, 0.63). Study limitations include the cross-sectional design, which precludes causal inferences; participants only providing a single stool sample; and, despite having a validation dataset that includes an external multi-center subset, the microbiome-based model was conducted in a smaller and single-center cohort, which needs to be further validated in a larger and multi-center cohort. The study authors concluded, “These findings support a stratified framework for older adults with [major depressive disorder], in which comorbid [REM behavior disorder] may delineate a subgroup with potential neurodegenerative risk.” Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. References: Yang Y, Li N, Zhou L, et al. Gut microbiome in depression with and without REM sleep behavior disorder. Mol Psychiatry. Published online July 23, 2026. doi:10.1038/s41380-026-03773-3