In a February 2020 study by the University of Oxford, it was said,
“There has been growing research linking the gut microbiome to the brain and behaviour, known as the microbiome-gut-brain axis. Most research has been conducted in animals, whilst studies in humans have focused on the role of the gut microbiome in neuropsychiatric conditions.”
The study was designed to, “look in the general population to see how variation in the types of bacteria living in the gut may be related to personality."
"This suggests that the gut microbiome may contribute not only to the extreme behavioural traits seen in autism but also to variation in social behaviour in the general population. However, since this is a cross-sectional study, future research may benefit from directly investigating the potential effect these bacteria may have on behaviour, which may help inform the development of new therapies for autism and depression."
“This is the first study to find a link between sociability and microbiome diversity in humans and follows on from similar findings in primates which have shown that social interactions can promote gut microbiome diversity. This result suggests the same may also be true in human populations."
"This is the first time this has been investigated in adults and the results suggest that infant nutrition may have long-term consequences for gut health."
"Our modern-day living may provide a perfect storm for dysbiosis of the gut. We lead stressful lives with fewer social interactions and less time spent with nature, our diets are typically deficient in fibre, we inhabit oversanitized environments and are dependent on antibiotic treatments. All these factors can influence the gut microbiome and so may be affecting our behaviour and psychological well-being in currently unknown ways."