"If I'm someone who doesn't like uncertainty, I may become more anxious, search further, monitor my body more, go to the doctor more frequently - and the more you search, the more you consider the possibilities," Thomas Fergus, Ph.D., an assistant professor of psychology and neuroscience in Baylor's College of Arts and Sciences, said.
"If I see a site about traumatic brain injuries and have difficulties tolerating uncertainty, I might be more likely to worry that's the cause of the bump on my head," he said.
As if fearing a catastrophic disease or injury isn't bad enough, doubts about health - unfounded or not - may trigger worries about potential medical bills, disability and job loss, he said.
And that can lead to even more Googling, obsessing, doctor visits, unnecessary medical testing and distress.
Prior research shows that approximately eight out of 10 American adults seek medical information on the Internet.
While fearing the worst when it comes to health is not new, the online glut of medical information - some of it from questionable sources - may be more disturbing than that contained in medical manuals that people consult or obtain directly from a doctor, Fergus said.
The study is published in the journal Cyberpsychology, Behavior and Social Networking.