Poring over your friends' Facebook timelines and showering their posts with likes may make them feel good, but it could be having the opposite effect on your own well-being.

That’s the conclusion drawn by a new study conducted by researchers at the University of California, San Diego and Yale University and published in the American Journal of Epidemiology [PDF]. After collecting data from over 5000 participants, researchers looked at the correlation between respondents' Facebook use (specifically how often they like posts, click links, and update their own statuses) and their self-reported mental health, physical condition, and overall life satisfaction.

What they found was that subjects who increased their use of the social media network reported a decreased sense of well-being, with a 5 to 8 percent reduction in mental health being the most significant finding. Writing for the Harvard Business Review, co-authors Holly Shakya and Nicholas Christakis noted: “We found consistently that both liking others’ content and clicking links significantly predicted a subsequent reduction in self-reported physical health, mental health, and life satisfaction.”

The study also examined the impact of in-person socialization with friends, finding that hanging out with people in real life was associated with increased life satisfaction—though the increase was by a smaller margin than the decrease associated with Facebook use.

Researchers don’t know exactly why there’s a correlation between Facebook use and a self-reported reduction in life quality: Liking posts was no more impactful than creating one’s own posts, minimizing the possibility that feeling socially inferior is to blame. Instead, the results indicated that quantity may be the most important variable, with more time spent online leading to a diminished sense of contentment. As the authors noted, “Large quantities of social media interaction may indeed detract from more meaningful real life experiences.”

[h/t Newsweek]