PROBLEM: Google overhyped the flu this year, which seemed to be a blow to the company's claim that it can track disease in real-time. Not to mention, the CDC was doing a fine job monitoring the virus's spread without the help of Google's search-based analysis. Traditional epidemiological surveillance techniques are less reliable, though, when it comes to mental illness, which remains complex and stigmatized enough that there's reason to believe people may be more comfortable consulting the Internet than their doctors.
METHODOLOGY: Public health experts at San Diego State looked at every mental health query made on Google between 2006 and 2010 in the U.S. and Australia. They identified searches that used "language suggestive of mental health matters," which usually involved people either attempting to self-diagnose or treat themselves, or looking up information on behalf of a friend or family member.
The researchers specifically analyzed this data in terms of seasonal changes: shorter, darker days are known to increase symptoms of depression, but little is known about possible patterns for other mental illnesses. They adjusted for big news stories, to avoid the effects of media hype like that which caused Google to suggest that the flu was more widespread than it actually was.