Neuroticism(神経質)may increase the risk of developing asthma in middle age. Animal studies have shown that chronic stress can affect hormone levels, which can lead to inflammation of the airway and cause breathing difficulties. Researchers believe that the excessive worrying and emotional ups and downs associated with neuroticism may have similar effects on human health. According to a recent study, individuals who were highly neurotic were three times more likely to develop asthma than those who were less neurotic.