There is lots of speculation surrounding the relationship between mental health and microbes. One mechanism that has been suggested is an indirect mechanism which involves microbes causing the release of cytokines, which in return causes the brain to carry out certain actions in response to the cytokine release. Another method is that neurotransmitters produced by certain microbes may be connecting with nerve endings in the stomach, sending signals to the brain to react accordingly. A third approach involves the byproducts of microbes, which are believed to be able to enter the receptive ends of the vagus and sympathetic nerves that report back to the brain.
Because it is believed that the brain and stomach are linked systematically, both are able to influence the other. It was previously discussed how the microbiota can influence mental health. One’s nervous system can also influence his microbial community. For instance, the presence of the vagus nerve is required for a certain microorganism to have any influence on the brain. Therefore, if the nervous system is damaged, it is possible that some microbes in the microbiota will be unable to exhibit their effects on one’s mental state.
Since the brain and microbiota appear to be linked, a steady relationship must be achieved if we want both to work properly. Ways to reach an optimally functioning relationship is to take probiotics or antibiotics as needed. Few studies have been done that show a relationship between antibiotic treatments and relieving ASD symptoms. However, we must be careful to not irreversibly disrupt our microbiota, as it heavily functions in other parts of our well-being.