Clinical, epidemiological, and immunological evidence suggest that enteric microbiota extensively and profoundly influences the gut-brain relationship (ie, mental state, emotional regulation, neuromuscular function, and regulation of the HPA). Research continues to elucidate mechanisms of action to explain the effects of microbiota, both directly and indirectly, on emotional and cognitive centres of the brain1 and has demonstrated that fluctuations of the microbiota are linked to changes within these systems of communication.2
For example, several mood disorders, such as anxiety, depression, and autism spectrum disorders now have well-established links to functional GI disruptions, whereas GI disease (eg, irritable bowel syndrome, irritable bowel disease) often involve psychological comorbidities associated with alteration of the gut microbiome.3-9 In addition, research has demonstrated that the composition of gut bacteria appears to be influential in fetal and neonatal neurologic development.10 And, not surprising, diet has also been shown to influence the gut microbiome’s impact on cognitive function.11
It isn’t anyone but the gut biome’s fault. It literally changes your personality in ways that are out of our control.
See: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6469458