Personality traits are unrelated to health (if you only measure traits that are unrelated to health)

In the NY Times, Richard Sloan writes:

It’s true that in some respects we do have control over our health. By exercising, eating nutritious foods and not smoking, we reduce our risk of heart disease and cancer. But the belief that a fighting spirit helps us to recover from injury or illness goes beyond healthful behavior. It reflects the persistent view that personality or a way of thinking can raise or reduce the likelihood of illness.

But there’s no evidence to back up the idea that an upbeat attitude can prevent any illness or help someone recover from one more readily. On the contrary, a recently completed study of nearly 60,000 people in Finland and Sweden who were followed for almost 30 years found no significant association between personality traits and the likelihood of developing or surviving cancer. Cancer doesn’t care if we’re good or bad, virtuous or vicious, compassionate or inconsiderate. Neither does heart disease or AIDS or any other illness or injury.

Sloan, a researcher in behavioral medicine, is trying to make a point about “a fighting spirit,” but in the process he makes a larger point about personality traits being unassociated with health. And when he overreaches, he is clearly and demonstrably wrong.

That study of 60,000 people (which the Times helpfully links to) used the Eysenck Personality Inventory and thus only looked at two personality traits, extraversion and neuroticism. They found no association between those traits and incidence of cancer or survival after cancer. But the problem is that the researchers didn’t measure conscientiousness, the personality trait factor that has been most robustly associated with all kinds of health behaviors and health outcomes (including early mortality).

Of course, conscientiousness isn’t really about upbeat attitude or a fighting spirit. It’s more about diligently taking care of yourself in many small ways over a lifetime. In that respect Sloan’s central point about “fighting spirit” isn’t disputed by the conscientiousness findings. (Researchers working in the substantial optimism and health literature may or may not feel differently.) Moreover, the moral and philosophical implications — whether we should praise or blame sick people for their attitudes — go well beyond the empirical science (though they certainly can and should be informed by it). But a reader could easily get confused that Sloan is making a broader point that personality doesn’t matter in health outcomes — and that just ain’t so.

I’m not sure Sloan intended to take such a broad swipe against personality traits, given that his own research has examined links between hostility and cardiac outcomes. Then again, browsing his publications leaves me confused. His op-ed says that being “compassionate or inconsiderate” has nothing to do with heart disease; but this abstract from one of his empirical studies concludes that “[trait] hostility may be associated with risk for cardiovascular disease through its effects on interpersonal interactions.” I haven’t read his papers — I just Google Scholared him this morning — so I’ll give him the benefit of the doubt that there’s some distinction I’m missing out on.

4 thoughts on “Personality traits are unrelated to health (if you only measure traits that are unrelated to health)

  1. This is interesting, and it seems to me to be a tricky line to toe sometimes.
    On the one hand, you do not want to give credence to cranks who tell people to forego chemo and read a self-help book about having a positive attitude to cure their cancer.
    On the other, it makes total sense that if you are an unconscientious, hostile asshole, it is going to have all sorts of bad effects on your well-being. I mean, how can alienating friends and not taking care of yourself not have any health consequences?

    I think the happiness people have to straddle this same line, showing the benefits of happiness, but admitting that they are only but so flexible.

    Maybe the hard part (it is the hardest science, right?) is admitting that some of these things like conscientiousness are more like rigid traits than flexible, “perspectives” that are subject to change by reminding ourselves to be good, virtuous and compassionate.

  2. Great comments. I’d like to draw your attention to a NYT article 11-5-2010 “As Life Alters Genes, Illness May Emerge.” The article refers to how people’s experiences and environment affects the function of their genes. There are some studies being funded by NIMH about this. I’m basically a social worker practitioner who is trying to bring the latest info to my patients. This material provides an extra sense of hope for changing outcomes.

  3. We published two pieces related to the Sloan op-ed that readers might find of interest.

    The first is titled Dr. Sloan Misses The Point: A Fighting Spirit Is Vital In Overcoming Illness and can be read at this link:

    The other is titled Fighting Spirit And The Challenge To Live and can be read at this link:

    Thank you very much.

    Jim Prevor

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