Study says Microbes in gut may contribute to social anxiety disorder

A recent study published in the Proceedings of the National Academy of Sciences (PNAS) suggests a potential link between social anxiety disorder (SAD) and gut microbes, highlighting the role of the gut microbiome in influencing brain function.

The study revealed that individuals with SAD have different gut microbes compared to those without the disorder. Researchers conducted experiments where they transplanted microbes from the guts of people with SAD into mice. The mice exhibited heightened sensitivity to social fear, along with changes in immunity and brain function.

John Cryan, a professor at the University College Cork in Ireland and co-author of the study, emphasized the significance of gut health in understanding and addressing psychiatric disorders like SAD. While genetic factors, environment, and other elements contribute to such disorders, the study focused on the impact of gut microbiota.

The researchers collected fecal samples from six healthy individuals and six people with SAD, identifying notable differences in the microbial composition between the two groups. Subsequently, they transplanted these samples into mice that had their microbiota eliminated by antibiotics. The mice underwent tests to evaluate sociability, social cognition, and stress-coping behaviors.

Results indicated that mice receiving gut microbes from individuals with SAD exhibited altered levels of three bacterial species in their feces compared to those receiving microbes from healthy individuals. Following social fear experiments, mice with SAD-associated microbiota showed persistent fear of approaching others, while those with healthy-associated microbiota regained curiosity towards other mice.

The study suggested a potential causal role of microbiota in heightened social fear responses associated with SAD. Cryan proposed that the findings could inform therapeutic approaches for individuals with SAD, such as dietary interventions aimed at altering the microbiome, such as increasing fiber and fermented foods in the diet. However, further research is needed to fully understand the complex relationship between gut microbes and mental health disorders.