The Microbiota-Gut-Brain Axis: Psychoneuroimmunological Insights

There is growing interest in the role that the intestinal microbiota and the related autoimmune processes may have in the genesis and presentation of some psychiatric diseases. An alteration in the communication of the microbiota-gut-brain axis, which constitutes a communicative model between the central nervous system (CNS) and the gastro-enteric tract, has been identified as one of the possible causes of some psychiatric diseases. The purpose of this narrative review is to describe evidence supporting a role of the gut microbiota in psychiatric diseases and the impact of diet on microbiota and mental health. Change in the composition of the gut microbiota could determine an increase in the permeability of the intestinal barrier, leading to a cytokine storm. This could trigger a systemic inflammatory activation and immune response: this series of events could have repercussions on the release of some neurotransmitters, altering the activity of the hypothalamic-pituitary-adrenal axis, and reducing the presence of trophic brain factors. Although gut microbiota and psychiatric disorders seem to be connected, more effort is needed to understand the potential causative mechanisms underlying the interactions between these systems.

Automated summary

There is increasing interest in the role of intestinal microbiota and autoimmune processes in psychiatric diseases. Altered communication between the microbiota-gut-brain axis may be a cause of psychiatric disorders. This review explores the evidence for the involvement of gut microbiota in psychiatric diseases and the impact of diet on microbiota and mental health. Changes in gut microbiota composition can lead to increased intestinal permeability, resulting in a cytokine storm, systemic inflammation, and immune response. These events can affect neurotransmitter release, alter the hypothalamic-pituitary-adrenal axis, and reduce trophic brain factors. Further research is needed to understand the underlying mechanisms connecting gut microbiota and psychiatric disorders.