A Gut Feeling: The Importance of the Intestinal Microbiota in Psychiatric Disorders

Abstract

The intestinal microbiota constitutes a complex ecosystem in constant reciprocal interactions with the immune, neuroendocrine, and neural systems of the host. Recent molecular technological advances allow for the exploration of this living organ and better facilitates our understanding of the biological importance of intestinal microbes in health and disease. Clinical and experimental studies demonstrate that intestinal microbes may be intimately involved in the progression of diseases of the central nervous system (CNS), including those of affective and psychiatric nature. Gut microbes regulate neuroinflammatory processes, play a role in balancing the concentrations of neurotransmitters and could provide beneficial effects against neurodegeneration. In this review, we explore some of these reciprocal interactions between gut microbes and the CNS during experimental disease and suggest that therapeutic approaches impacting the gut-brain axis may represent the next avenue for the treatment of psychiatric disorders.

Keywords: gut/brain axis; immunoregulation; microbiome; neuroinflammation; neurological disorders.

Figure 1

Multifactorial interactions occurring between the intestinal microbiota and products and the CNS. The CNS and the gut microbiota are connected reciprocally through the hypothalamic-pituitary-adrenal (HPA) axis, the immune system, and the neuronal system. These interactions have critical impacts on immune homeostasis, intestinal barrier permeability and the integrity of the blood brain barrier and can regulate CNS inflammation and disease.