The role of gut-brain axis in mood disorder

Abstract

The connection between the gastrointestinal system (GI) and the central nervous system (CNS), together with the performance of the enteric nervous system (ENS), forms a complex communication network called the “gut-brain axis”. Scientific evidence indicates that the gut microbiota coordinates a multitude of bodily functions, closely linked to the immune, metabolic and nervous systems. In this context, any alteration that occurs in the “gut-brain axis” will result in damage to the homeostasis of the systems, because a dysfunction of the intestine-brain axis can lead to a dynamic impairment of the action of the protective barriers of the intestinal walls. Through directional gut-brain communication, the changes detected in the gastrointestinal tract affect the neurochemical transformations that occur in the CNS. The recognition of the relationship of neural aspects to the dynamics of the human microbiome contributes to the emergence of physiological imbalances that can contribute to the worsening of a wide spectrum of psychiatric disorders, with emphasis in the literature on anxiety disorders, depression, and autism spectrum disorders (ASD), schizophrenia and attention-deficit hyperactivity disorder (ADHD). The present literature review aims to verify the function and impact of the gut-brain axis in mood disorders, aiming to identify and strengthen evidence that the brain and gut have a strong and intimate connection responsible for the modulation of neurons, neurotransmitters, hormones and immunological mediators.