Figure 1.

The microbiome-gut-brain axis in psychiatry. A number of factors have an influence on the assembly, composition and stability of the gut microbiota including mode of birth, lifestyle factors such as diet and exercise, and stress. These factors could thus impact signaling along the microbiome-gut-brain axis, which has been implicated in a variety of behavioral features relevant to schizophrenia and autism including anxiety and cognition. This impact may be underpinned by microbial regulation of the host immune system, CNS BDNF expression and microglial activation states.