Social anxiety disorder (SAD) is a common psychiatric disorder characterised by fear or anxiety in regards to social situations such as having a conversation, meeting new people, being observed or having to speak or perform in front of others. The current primary treatment includes selective serotonin reuptake inhibitors, serotonin and norepinephrine reuptake inhibitors and cognitive behavioural therapy, however a large portion of patients fail to respond to these treatments. There is a growing interest in the role of the gut microbiome in neurology, however not specifically in relation to SAD. The authors of this paper wished to assess whether the microbiome of those with SAD had compositional differences to individuals without SAD. Using 49 faecal samples, the researchers analysed differences in the gut microbiome of patients with SAD in comparison to individuals without SAD. Overall microbiota composition was found to be different between the SAD and non-SAD group, including differing species of bacteria as well as the microbiota functioning differently. The authors suggest that further research should be conducted in order to understand the implications of these differences.
The microbiome-gut-brain axis plays a role in anxiety, the stress response and social development, and is of growing interest in neuropsychiatric conditions. The gut microbiota shows compositional alterations in a variety of psychiatric disorders including depression, generalised anxiety disorder (GAD), autism spectrum disorder (ASD) and schizophrenia but studies investigating the gut microbiome in social anxiety disorder (SAD) are very limited. Using whole-genome shotgun analysis of 49 faecal samples (31 cases and 18 sex- and age-matched controls), we analysed compositional and functional differences in the gut microbiome of patients with SAD in comparison to healthy controls. Overall microbiota composition, as measured by beta-diversity, was found to be different between the SAD and control groups and several taxonomic differences were seen at a genus- and species-level. The relative abundance of the genera Anaeromassillibacillus and Gordonibacter were elevated in SAD, while Parasuterella was enriched in healthy controls. At a species-level, Anaeromassilibacillus sp An250 was found to be more abundant in SAD patients while Parasutterella excrementihominis was higher in controls. No differences were seen in alpha diversity. In relation to functional differences, the gut metabolic module ‘aspartate degradation I’ was elevated in SAD patients. In conclusion, the gut microbiome of patients with SAD differs in composition and function to that of healthy controls. Larger, longitudinal studies are warranted to validate these preliminary results and explore the clinical implications of these microbiome changes.
Article Publication Date: 20/03/2023