Longitudinal study of gut microbiome in obsessive-compulsive disorder

Area of Science:

• Microbiome research
• Neuroscience
• Psychiatry

Background:

• Obsessive-compulsive disorder (OCD) is associated with environmental limitations and repetitive behaviors.
• These behaviors may influence the gut microbiome, prompting investigation into its role in OCD.
• Cognitive behavioral therapy, specifically exposure and response prevention (ERP), is a key treatment for OCD.

Purpose of the Study:

• To investigate longitudinal changes in the gut microbiome of OCD patients before and after ERP therapy.
• To compare the gut microbiome composition and function between OCD patients and healthy controls (HCs).

Main Methods:

• 64 participants (32 OCD patients, 32 HCs) underwent psychiatric assessment and nutritional evaluation.
• Stool samples were collected from OCD patients pre-ERP and post-ERP (1 month), and from HCs.
• Microbiome whole genome sequencing was used for taxonomic and functional analyses.

Main Results:

• OCD patients consumed significantly less fiber than HCs at baseline.
• No significant differences in gut microbiome diversity (alpha and beta) or species-level taxonomic composition were found between OCD patients and HCs, or within OCD patients before and after ERP.
• No significant differences in the expression of 56 neuroactive gut-brain modules were observed between groups or over time.

Conclusions:

• The gut microbiome's diversity, composition, and functional profile in OCD patients are not significantly different from HCs.
• The gut microbiome remains stable in OCD patients over time, even after undergoing ERP therapy.
• These findings suggest the gut microbiome may not be a primary factor affected by behavioral changes in OCD.