The gut microbiome in social anxiety disorder: evidence of altered composition and functionOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study asked whether the gut microbiome differs in social anxiety disorder (SAD) compared to healthy people. The researchers used whole-genome shotgun metagenomic sequencing of faecal samples. They compared overall composition (beta and alpha diversity), specific taxa, and microbial functions. Functional capacity was assessed using gut-brain modules and gut-metabolic modules. Models adjusted for age, sex, BMI, exercise, and dietary differences. Differential abundance was tested with the ALDEx2 method and false discovery rate correction.
Who was studied?
The cohort was 49 adults in Ireland: 31 patients with clinically diagnosed SAD and 18 sex- and age-matched healthy controls. Ages ranged from 18 to 65 years. SAD diagnosis followed DSM-5 criteria confirmed by a psychiatrist. Almost three-quarters (74.2%) of patients had a past history of major depression, and 67.7% were taking psychotropic medication. Controls had no past or current psychiatric diagnosis. SAD patients had higher BMI and lower exercise levels than controls.
What were the most important findings?
Overall composition differed by beta diversity (PERMANOVA p = 0.038), while alpha diversity did not differ. Three genera and two species were significantly different after correction. At genus level, Anaeromassilibacillus and Gordonibacter were enriched in SAD, while Parasutterella was higher in controls. The species Anaeromassilibacillus sp. An250 appeared in 48.4% of SAD samples (15 of 31) but only 5.6% of controls (1 of 18), padj = 0.024. Parasutterella excrementihominis was enriched in controls (padj = 0.042). The gut-metabolic module aspartate degradation I was elevated in SAD patients.
What are the greatest implications of this study?
This is the first report that the gut microbiome is compositionally and functionally altered in social anxiety disorder. The differences remained after adjusting for BMI, diet, and other factors. The findings add to evidence linking the microbiome-gut-brain axis to social brain function. Several altered taxa belong to Clostridiales groups also shifted in autism and depression. The sample was small and cross-sectional, so causation cannot be inferred. The authors call for larger, longitudinal studies to validate these preliminary results.