There are research studies focusing on the correlation of germs or bacteria with one's mental health. The exposure to germs at a young age will lead to the person developing a stronger immune system as he or she gets older. The stronger the immune system of the person is, the stronger his or her mental health too.
Researchers found out that the low asthma rates in Amish children are due to in part to the exposure of the children during their infancy to germs or "old microbes". These germs or old microbes come from the dust around the Amish farms. These dust, scientifically called endotoxins, come from bacteria-rich soil typical of farming communities.
The simple Amish life is thriving with endotoxins but these endotoxins actually make the immune system of the Amish children to become stronger; Thus the low rates of asthma on Amish children. What does low asthma rates have to do with mental health?
Researchers are claiming that asthma is a kind of immune system disorder. A weak immune system leads to inflammation due to allergies, autoimmune reaction or infection. The studies claim that if a person has inflamed immune system, it means its immune system is producing high levels of cytokines. Cytokines triggers mental health problems like depression, social avoidance, inactivity, and others.
Researchers are saying that one way to prevent mental disorders is to study its correlation with the level of health of one's immune system. But further studies are still needed to be done to further investigate this claims.
Some researchers say that the health of the immune system is just one of the factors affecting mental health. Take for example the Amish community, Amish people are less prone to mental health problems due in part to their religious faith, strong ties with the community, and healthy lifestyles.