No, seriously... that question is not rhetorical.
I highly recommend Paul Martin's [no, not the former Canadian Prime Minister] The Healing Mind: The Vital Links Between Brain and Behavior, Immunity and Disease. [published 1997].
The principle argument or theme is that disease and death seldom have single causes. There is a link between what goes on in the mind, and what goes on in the body.
This particular branch of study is known as "psychoneuroimmunology".
Try saying that with a mouthful of crackers!
Contemporary physicians and scientists frequently dismiss the idea that the mind has any marked effect on physical health. The fact is that most people, doctors and scientists included, find it inherently easier to believe in the reality of apparently simple physical causes of disease (such as cholesterol, salt, smoking, lack of exercise, bacteria or viruses) than to accept that mere thoughts can affect our health. There are extremists on either side of the spectrum; those that claim that the mind/emotions have no influence whatsoever, and the New-Age gurus who believe that adopting certain thinking patterns can prevent cancer!
Dr. Martin's familiarity with well-documented research, authoritative commentary, and overall witty style combine to present a very convincing argument for a middle ground conclusion: that the relationships between mind, body and disease work both ways. The mind affects the body and hence physical health (negatively AND positively). Conversely, physical health affects the mind and hence our thoughts, emotions and behaviour.
Throughout the book, he alludes to examples in literature to illustrate these links between psychological factors and disease. These illustrations help to convey complex scientific ideas in a recognizable form, and I found this feature very innovative and effective... lifting the weight from some very heavy ideas, and making me say, "Of course, I get it now."
There is an extensive discussion of that modern-day source of malady... STRESS. How does "stress" make us more susceptible to breakdown and disease? Interesting sections on the Type A personality (typified by free-floating hostility, aggressiveness, competitiveness, impatience) and how it lends itself to increased risk of heart disease. Also, a section on the Type C personality (typified by suppression of strong emotions, avoidance of conflict, compliance with the wishes of others) and how it lends itself to increased risk of cancer.
A fascinating book!
Incidentally, my copy is old, and bears the original title, which was "The Sickening Mind". Read the newer "Healing Mind" and find out for yourself just how appropriate both titles actually are!