Gut microbiota in major depressive disorders with and without Rapid Eye Movement Behavior Disorder: tracing a subtype of depression with underlying neurodegeneration
Depression is a heterogeneous disease with an overall unsatisfactory response rate despite intensive treatment. Previous studies have elicited the evidence that depression is associated with a higher risk for subsequent neurodegeneration, such as α-synucleinopathy disorders including Parkinson’s disease (PD) and dementia with Lewy bodies (DLB), and tauopathy (Alzheimer’s disease). Nonetheless, it remained unclear on the intricate relationship between depression and subsequent risk of neurodegeneration on the pathophysiological mechanism as well as to the type of neurodegeneration. Idiopathic Rapid eye movement (REM) sleep behavior disorder (iRBD) has been confirmed as the most predictive and specific risk factor of α-synucleinopathy. RBD features have been increasingly reported in patients with major depressive disorder (MDD) and antidepressants use (especially serotonin selective reuptake inhibitors, SSRI). Previous evidence including our data has suggested that MDD+RBD is not just an epiphenomenon of the pharmacological effect of antidepressants, but likely clustering with the underlying α-synucleinopathy neurodegenerative process.
The gut and brain communicate bi-directionally, and growing attention has been paid to the role of gut microbiota in the pathogenesis of mental illness and neurodegenerative disorders including PD. For example, significant differences in the microbial diversity and taxonomic compositions have been revealed in patients with MDD, and subjects with PD showed distinct microbial composition and alterations of individual microbes, such as the depletion of anti-inflammatory short-chain fatty acids (SCFA)-producing bacteria. A recent study including our data also revealed similar microbial changes between typical RBD and PD patients. Nonetheless, it remained unclear whether the gut microbiota might have a distinct composition profile when comparing between the MDD patients with and without RBD, and whether the MDD+RBD patients will have a similar shift in microbial composition as in patients with typical iRBD or PD patients, as well as on the possible association between microbial changes with the clinical symptoms of these patients. Thus, the current study is proposed aiming to resolve these knowledge gaps and improve the subtyping of MDD and understanding of neurodegeneration predisposition in these patients.
Patients with depressive disorders (with or without RBD features) and healthy control subjects. Total sample size targeted at 224.
We hope to invite you to Shatin Hospital or other related research sites for this study If the visit is inconvenient to you, we may also arrange home visits alternatively.
- Questionnaires
- Clinical interviews (sleep and mood assessments)
- Neurocognitive tests
- Stool sample collection
- Blood examination
- Overnight sleep assessment (Applicable to the situation when RBD features have never been assessed before)
Procedures last around 2 hours, overnight sleep assessment require further arrangements.
All assessments are free of charge and each participant will receive HK$100 cash coupon as travel allowance.
