Is Anxiety Associated with the Gut Microbiota?

Understanding how the microbiome influences health and disease has emerged as an important area of research across all domains of biomedical and health sciences. An extensive body of work in animal models has established a link between the gut microbiome and anxiety-like behaviour. Foundational work on germ-free mice provided the catalyst for neuroscientists to consider the microbiota-brain axis and brain health. Research manipulating the microbiome, including use of germ-free mice, antibiotics, and probiotics, provide evidence that the microbiota influences stress systems and in particular anxiety-like behaviour. Consideration of anxiety-like behaviour in animal models of metabolic and inflammatory disorders expands the scope of the work and correlates in clinical studies are emerging. This chapter highlights the work done to date in animal studies and reviews the recent clinical literature translating these observations to anxiety disorders.