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.

In the U.S., inquiries about mental health dropped by 14 percent from winter to summer. The seasonal differences, for major mental illnesses, were:

  • Eating disorders: 37%
  • Schizophrenia: 37%
  • Bipolar: 16%
  • ADHD: 28%
  • OCD: 18%
  • Suicide: 24%
  • Anxiety: 7%

"We can figuratively look inside the heads of searchers to understand population mental health patterns" by analyzing Google searches, said lead researcher John Ayers in a statement.

Read more from The Atlantic.