The gut-brain connection: A qualitative review of the conceptualisation and implications of the gut-brain-microbiome axis

Abstract

Current research shows that the gastro-intestinal and central nervous systems are linked by multiple interconnecting layers and have been known to continually influence each other’s actions. The enteric nervous system, vagus, hypothalamic pituitary axis, and the local endocrine system are few of the components of this complex system, forming neurological, immunological as well as endocrine bridges through which information relay occurs. In addition, the gut microbiota exerts overarching influence on all these components, directly and indirectly affecting the brain and impacting human behaviour. This, in effect, creates a gut-brain-microbiotal (GBM) axis, which has a potential role in various physiological functions. It is also implicated in pathological processes as well, and is found to have a role in many psychiatric conditions such as autism spectrum disorders, schizophrenia, mood disorders, substance use and neurodegenerative disorders. The mechanisms involved in each disorder, as well as psychological correlates of the GBM axis, along with potential treatment implications involving microbiota and possible strategies to modulate microbiota to affect changes in psychiatric symptoms are explored in this article.

Keywords

• gut-brain axis
• gut microbiota
• gut-brain microbiota axis in psychiatric disorders
• psychobiotics.