Sarah E. Hampson
Although the belief that personality is linked to health goes back at least to Greek and Roman times, the scientific study of these links began in earnest only during the last century. The field of psychosomatic medicine, which grew out of psychoanalysis, accepted that the body and the mind were closely connected. By the end of the 20th century, the widespread adoption of the five-factor model of personality and the availability of reliable and valid measures of personality traits transformed the study of personality and health. Of the five broad domains of personality (extraversion, agreeableness, conscientiousness, emotional stability, and intellect/openness), the most consistent findings in relation to health have been obtained for conscientiousness (i.e., hard-working, reliable, self-controlled). People who are more conscientious have better health and live longer lives than those who are less conscientious. These advantages are partly explained by the better health behaviors, good social relationships, and less stress that tend to characterize those who are more conscientious. The causal relation between personality and health may run in both directions; that is, personality influences health, and health influences personality. In addition to disease diagnoses and longevity, changes on biomarkers such as inflammation, cortisol activity, and cellular aging are increasingly used to chart health in relation to personality traits and to test explanatory models. Recognizing that both personality and health change over the life course has promoted longitudinal studies and a life-span approach to the study of personality and health.