Insomnia in Parkinson's disease is associated with distinct gut microbiome profiles compared with non-PD individuals, with opposite directions of alpha diversity change and entirely non-overlapping functional pathways between the two groups.
Key Findings
Results
Insomnia was associated with higher alpha diversity in non-PD individuals but lower alpha diversity in PD patients.
Study analyzed 310 participants: 185 PD patients and 125 controls categorized by insomnia status.
The direction of the association between insomnia and microbial alpha diversity was opposite in PD versus non-PD groups.
Interaction analysis statistically confirmed that the associations between insomnia and microbial diversity were distinct in the two groups.
Gut microbiome profiles were obtained using 16S rRNA sequencing processed with DADA2 using the SILVA database for taxonomic assignment.
Results
Differential abundance analysis identified unique insomnia-associated bacterial genera in PD patients versus non-PD controls, with differing insomnia-risk-reducing and insomnia-risk-increasing taxa between groups.
The specific bacterial genera associated with insomnia risk did not overlap between PD and non-PD individuals.
Both insomnia-risk-reducing and insomnia-risk-increasing taxa differed between the two groups.
Analysis was conducted adjusting for relevant confounders.
The findings suggest disease context fundamentally alters which microbiota are linked to insomnia.
Results
Functional pathway analysis revealed six enriched pathways associated with insomnia in non-PD controls but only two enriched pathways in PD patients, with no overlap between the groups.
Functional prediction was performed using PICRUSt2.
Controls showed six enriched microbial functional pathways associated with insomnia.
PD patients showed only two enriched microbial functional pathways associated with insomnia.
There was no overlap in enriched pathways between the PD and non-PD groups, indicating entirely distinct functional microbiome signatures.
Methods
Beta diversity analysis was conducted to examine community-level compositional differences between insomnia and non-insomnia groups within PD and non-PD individuals.
Both alpha and beta diversity analyses were performed as part of the microbiome characterization.
The study used 16S rRNA sequencing to profile gut microbiome composition.
DADA2 pipeline with the SILVA database was used for taxonomic assignment.
Analyses were adjusted for relevant confounders.
Conclusions
The study demonstrates heterogeneity in the gut microbiota–insomnia relationship moderated by Parkinson's disease status, highlighting the importance of disease context when examining microbiome-sleep relationships.
PD patients (n=185) and controls (n=125) were compared across insomnia status groups.
The authors conclude that insomnia in PD is associated with distinct gut microbiome profiles compared with non-PD individuals.
The results suggest that microbiome-based approaches to sleep disturbances may need to be tailored to whether or not a patient has PD.
The findings are described as informing 'future research on microbiome-based approaches for sleep disturbances in PD.'
What This Means
This research suggests that the relationship between gut bacteria and insomnia is not the same in everyone — it depends heavily on whether a person has Parkinson's disease (PD). In a study of 310 people (185 with PD and 125 without), researchers found that insomnia was linked to greater diversity of gut bacteria in people without PD, but to lower diversity in those with PD. This is a striking reversal: what looks 'worse' in one group looks 'better' in the other, suggesting that Parkinson's disease fundamentally changes how the gut microbiome relates to sleep problems.
The researchers also found that the specific types of bacteria associated with insomnia risk were completely different between PD patients and healthy controls, with no shared bacterial genera. Similarly, when they looked at what the bacteria were functionally doing (using a computational tool called PICRUSt2), they found six enriched biological pathways linked to insomnia in people without PD, but only two different pathways in PD patients — with zero overlap between the lists. This means the biological mechanisms connecting gut bacteria to insomnia appear to be entirely distinct in people with versus without Parkinson's disease.
These findings matter because they challenge a one-size-fits-all view of gut health and sleep. This research suggests that treatments or interventions targeting gut bacteria to improve sleep would likely need to be designed differently for people with Parkinson's disease than for the general population. It also underscores the importance of considering a person's disease background when studying or interpreting gut microbiome data related to sleep.
Lin S, Lin R, Chang R, Huang Y, Hsu Y, Chu C, et al.. (2026). Heterogeneity in the association between gut microbiota and insomnia moderated by Parkinson's disease status.. Frontiers in cellular and infection microbiology. https://doi.org/10.3389/fcimb.2026.1691665