(CNN) -- When you click "Like" on your friends' Facebook posts, do you really mean it?
If seeing your Facebook friends living wonderful, fun-filled lives gives you a case of the blues, you're not alone. A new University of Michigan study found that the more people checked Facebook, the more likely they were to feel worse about their own lives.
To measure people's feelings and Facebook usage, the team enlisted a small group of young adult Facebook users in Michigan and texted them five times a day for two weeks. Each text linked to an online survey that asked how they were feeling. In addition to reporting how much they were checking Facebook, the subjects rated their worry and loneliness levels at that moment as well as their overall satisfaction with life.
The authors also asked people to rate their level of life satisfaction at the start and end of the study, and found that the more participants used Facebook over the two-week study period, the more their life satisfaction levels declined. By contrast, the study found that face-to-face interactions with others led people to feel better over time.
"Over a billion people belong to Facebook, and over half of them log in every day," said University of Michigan social psychologist Ethan Kross, lead author of the study. "On the surface, Facebook provides an invaluable resource for fulfilling the basic human need for social connection. But rather than enhancing well-being, our findings demonstrate that interacting with Facebook may have the opposite result for young adults."
What is it about the social network that bums some people out? One theory is that people are comparing themselves to their friends' seemingly fantastic digital lives and feeling inferior.
Though the sample group of 82 people was small, the findings are similar to other studies about Facebook use and mental health.
Facebook has become a tempting subject for researchers because of its role as a constant presence in so many people's lives. Psychologists, sociologists and other academics are curious about what kind of impact it has on its users' brains, emotions and self-worth.
Some researchers have tapped directly into the gold mine of data generated by the social network (Facebook has its own staff of data scientists and sometimes teams up with universities), while others conduct their own independent studies.
In early 2012, a study out of Utah Valley University also found that many people had a case of the blues after checking Facebook. The researchers talked to a group of 425 students and found correlations between the amount of time people spent checking Facebook and negative feelings about their own lives. The more time their subjects spent on the social network, the higher probability that they would think their friends lived better, happier lives.
In January, a study from Germany found that a third of people felt worse after spending time on Facebook. Seeing updates of friends' successful careers, cute babies and fabulous vacations inspired feelings of envy, loneliness and even anger.