According to a new study in Psychoneuroendocrinology psychological problems, such as stress and anxiety, aggravate allergic reactions! As you know, this is one of many examples of the intimate connection between the well-being of the brain and the rest of the body I discuss here.
Often, this connection can lead to a vicious cycle, in which a broken body undermines the integrity of the mind, which exacerbates health problems. Mental illnesses can take a serious toll on your physical well-being which will compromise, in some cases, your sanity.
The broaden-and-build theory of positive emotions suggests that positive emotions broaden your awareness and probilify a variety of novel and exploratory thoughts and actions. Recent research seems to show that stress encourages perseveration, and causes significant, negative, changes in the neural architecture of the brain.
Perhaps this research will eventually yield the 'constrict-and-destroy theory of negative emotions'...