SCIENCE / MEDICINE : Depression Dismissed as Cancer Risk Factor
Many factors may raise the risk of cancer--but depression is not one of them, according to a recent study reported in the Journal of the American Medical Assn.
Researchers followed a sample of 6,403 men and women who were part of a national health survey.
On two standard psychological tests that measure self-reported depressive feelings, 1,002 subjects had symptoms of depression, such as crying spells, insomnia, loss of appetite or poor concentration.
Ten years later, 11% of those who had shown such symptoms had cancer, but so did 10% of the non-depressed group--a statistically insignificant difference. In both groups, 4% of the subjects had died of cancer.
This research, from the National Institute on Aging in Baltimore, provides the most convincing evidence to date disputing the so-called “cancer / attitude connection” and contradicts a number of older studies suggesting that depression might be a risk factor of cancer.
The first large study on the subject in 1981 concluded that depressed men more than doubled their risk of cancer. This and other studies since then postulated that depression has an adverse effect on the immune system that predisposes depressed individuals to cancer.
But these studies were either poorly designed, looked at a sample too small to be valid or did not take into account other factors that separately might have contributed to the development of depression or cancer.
The National Institute on Aging study considered subjects’ age, sex, marital status, smoking, family history of cancer, hypertension and cholesterol level.
The study’s conclusions call into question the theory that depression contributes to a “cancer personality”--and, by implication, that those who have cancer bear some responsibility for it.
That negative thinking makes you sick is the converse of the popular belief that positive thinking keeps (or can make) you well. Indeed, it is empowering to feel that you can take charge of your health through your attitude, and a number of best sellers purportedly describe just how to do so.
Common sense dictates that it cannot hurt to make the most of daily life, and certainly no doctor would suggest that depression plays a positive role in health.
But the danger with the “power of positive thinking” reasoning is that for those who do become ill, it can lead to self-recrimination.
The news from the National Institute on Aging lifts this load: If you are depressed, you need not add to your worries the fear that you are leaving yourself open to cancer. And if you have cancer, it’s not the fault of your psyche.
