A vial of saliva harbours a wealth of genetic information, and companies are mining this treasure trove to provide the public with personal disease-risk profiles. Some experts have questioned whether people might misinterpret such complex information and become anxious, but a study published today in the New England Journal of Medicine1 seems to debunk that idea. Test results also failed to prompt changes in diet and exercise. Direct-to-consumer genetic tests, such as those offered by personal-genomics companies 23andMe in Mountain View, California, and Navigenics in Foster City, California, scan an individual's DNA for a whole host of disease-related genetic variants. “The concern was if people hear that they're at risk of developing a scary disease, they would be terrified,” says Robert Green, co-director of the Alzheimer's Disease Clinical and Research Program at Boston University in Massachusetts, who was not involved in the study. Spurred by anxiety, people could then ask for unnecessary screening — pushing up health-care costs.
A previous study found that genetic testing for Alzheimer's diesease had no impact on anxiety2. But a team led by Eric Topol, a professor of translational genomics at the Scripps Translational Science Institute in La Jolla, California, has now looked at the effect on psychology and behaviour of commercially available genome-wide scans focused on a range of diseases. “This is an area that has been in the dark matter of our knowledge base,” says Topol.