The Limits of Personalized Medicine

A new study suggests that knowing their genetic risk of disease doesn’t motivate people to change their behavior.

Jonathan Alcorn / Reuters

Personalized medicine—the idea that genetic testing can reveal a person’s unique risks for various illnesses, as well as the most effective treatments—has attracted a huge amount of attention over the past few years. While the concept includes promising approaches to things like cancer treatment, much of the focus has been on using genetic risk information to motivate healthy lifestyles. In his 2015 State of the Union address, President Obama suggested that future advances in biomedicine would provide the “personalized information we need to keep ourselves and our families healthier.” Francis Collins, the director of the National Institutes of Health, has suggested that personalized medicine “means taking better care of ourselves.”

In the context both men are describing—living healthier lifestyles to prevent chronic disease—the promise of personalized medicine lies in its ability to inspire behavior change. Having this genetic information isn’t inherently helpful; it’s what people do with the information that matters.  But new research suggests that knowing one’s genetic risk isn’t enough to get people to quit smoking, eat better, or otherwise take actions to improve their health.

In a study published on Tuesday in BMJ, researchers from Cambridge University’s Health and Behavior Research Unit analyzed 18 past papers on the link between knowledge of genetic risk and health-behavior change. Their takeaway from the review: “Expectations that communicating DNA-based risk estimates changes behavior are not supported by existing evidence.”

“These results do not support use of genetic testing or the search for risk-conferring gene variants for common complex diseases on the basis that they motivate risk-reducing behavior,” they wrote.

This isn’t the first time researchers have arrived at that conclusion—many past studies, for example, have suggested that knowing one’s genetic-risk information doesn’t have a significant impact on smoking behavior, weight loss, or adherence to lifestyle advice, even when the genetic information is accompanied by counseling.

But given the momentum around personalized medicine and the continued growth of the direct-to-consumer genetic-testing industry, it remains to be seen how much of an impact these findings will have on the direction of future research.

In certain situations, the institutional reverence for personalized medicine may be misguided or even detrimental: It distracts people from more evidence-based approaches to improving population health. It feeds into the myth that living a healthy lifestyle requires complicated solutions, which may, paradoxically, hurt efforts to sustain behavior change or discourage individuals from even trying.  And it helps to legitimize the marketing of unproven genetic-testing services.

In addition, a focus on personalized approaches to health may subtly shift responsibility away from social institutions and toward individuals. There is at least some evidence that this kind of framing may hurt public support for population-based public-health interventions. Diet, exercise, substance use—all those are driven by structural factors as much as, or more than, personal choice. Genetic testing won’t change that.