A clean home can weaken the immune system and affect the brain in the process, according to a study published in the journal Molecular Psychiatry.
Previous studies have linked clean homes to weakened immune systems since occupants are rarely exposed to bacteria that could help them develop a resistance to some illnesses.
This latest study suggests that those with weaker immune systems tend to overreact to dust and dirt with inflammations or allergies, which in turn, can slow the brain’s production of ‘happy’ chemicals like serotonin.
Thus the researchers have linked cleanliness to allergies to depression. Rates of depression are far higher in the developed world than in poorer parts of the planet, say researchers, leading them to their unusual conclusion.
“We believe the immune system is causing depression,” said lead author Dr Andrew Miller. “As people develop and grow up, their immune system develops. If they are exposed to more bacteria and parasites, they are able to better control the inflammation.
“Nowadays, people’s environment is much cleaner and hygienic so our immune system never really learns how to deal with infectious agents.”