Your ability to withstand stress-related, inflammatory diseases may be related to your personality. Especially in aging women, a lack of the personality trait known as extroversion may signal that blood levels of a key inflammatory molecule have crossed over a threshold linked to a doubling of risk of death within five years.
A study found that that extroverts, and in particular those high "dispositional activity" or engagement in life, have dramatically lower levels of the inflammatory chemical interleukin 6 (IL-6). Extroverts tend to be focused on the world around them and are most happy when active and surrounded by people. Introverts look inward and are shy.
For the study, degree of extroversion was determined by standard tests, including the NEO Five-Factor Inventory. The study found that the difference between the 84th percentile of dispositional activity and the 16th translated roughly into a 1.29 picogram increase in IL-6 per milliliter of blood.