There is mounting evidence that imbalances in the gut microbiome are related to cognitive and behavioural problems, including autism spectrum disorder  and attention-deficit hyperactivity disorder (ADHD) .
An important study of infant microbiomes in healthy infants found that there were basic profiles of bacteria, as measured in the feces, that were able to predict the cognitive abilities of the same children at 2 years of age (Carlson et al, 2018). Interestingly, those with profiles that related to cognitive function were likely to be breastfed, had a higher birth weight, and were born by caesarean section.
There is further evidence that prebiotic support can shift the profile of the microbiome to a more favourable profile. In a study that compared the effects of a GOS-based prebiotic on bacterial profiles in autistic children , the prebiotic use resulted in a profile that resembled that of non-Autistic children, and increased the levels of Bifidobacteria, a type of bacterium promoted by breastfeeding.
A separate study published by the same researchers <sup”> also found that autistic children who were give a GOS prebiotic showed behavioural improvements, as well as a bacterial profile that was similar to the profiles reported by Carlson et al. (2018).
Taken together, these studies suggest that improving the gut microbiome may lead to improvements in behaviour, in children with behavioural problems via the gut-brain axis.