It is health that is real wealth and not pieces of gold and silver.
An important literature review by Ian Deary, Alexander Weiss, and David Batty (2010) was recently published that looked at the links between personality traits - specifically the often-studied Big Five (neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness) - and health, measured as disease and death, as inflammatory markers, and as health-relevant behaviors. Their review also looked at the link between intelligence and health.
Notable about this review was that it focused on large and representative sample studies that spanned many years. Hard outcomes - i.e., not self-report - were privileged, including of course death (which I suppose would be difficult to measure by self-report). The authors addressed as possible the mechanisms leading from these psychological characteristics to health outcomes, acknowledging that confounds abounded.
I worked my way carefully through their report, which was long and detailed. Bottom line: Psychological characteristics matter for physical well-being, and the magnitudes of the effects are meaningful. Those with lower intelligence are less healthy, as are those who are higher on neuroticism and lower on the other Big Five traits, especially conscientiousness. Cardiovascular disease is more under the sway of psychological variables than cancer. The mechanisms - alas - are not clear, but they may include how people behave, their attained socioeconomic status, and the relationships they establish with the health care system, including specific doctors.
So what's the positive psychology point? Most generally, psychological characteristics matter when our concern is with physical health, perhaps as much or even more than the usual biological risk factors of cholesterol, blood pressure, and body-mass index. More attention should be paid to these by the health care professions. Psychology is not soft, at least in terms of what it can predict, and positive traits like conscientiousness can predict a lot.
The authors of this review do not believe that personality as measured by the Big Five can be changed. I disagree, especially with respect to some of the so-called facets of the Big Five, but I will not belabor the point. Rather, I will mention with approval their recommendations that information about patient intelligence and personality makeup can be useful to the health professional (and to the health consumer) in terms of who to monitor for health problems, how to tailor treatments for particular individuals, and how to improve the relationships between health professionals and their patients. Knowledge is power, and in the case of physical health, powerful stuff indeed.
Deary, I. J., Weiss, A., & Batty, G. D. (2010). Intelligence and personality as predictors of illness and death: How researchers in differential psychology and chronic disease epidemiology are collaborating to understand and address health inequalities. Psychological Science in the Public Interest, 11, 53-79.