For young adults, social media may not be so social after all.

Among people in that age group, heavy use of platforms such as Facebook, Snapchat and Instagram was associated with feelings of social isolation, a study finds.

The results surprised study co-author Brian Primack. “It’s social media, so aren’t people going to be socially connected?” he says. He’s director of the Center for Research on Media, Technology and Health at the University of Pittsburgh. And while his team’s previous research connecting social media use and depression in young adults wasn’t terribly surprising, these new results seemed counterintuitive.

While face-to-face social connectedness is strongly associated with well-being, it’s not clear what happens when those interactions happen virtually.

It turns out that the people who reported spending the most time on social media — more than two hours a day — had twice the odds of perceived social isolation than those who said they spent a half hour per day or less on those sites. And people who visited social media platforms most frequently, 58 visits per week or more, had more than three times the odds of perceived social isolation than those who visited fewer than nine times per week.

This study can’t nail down causation. It could be that when people feel socially isolated, they go online a lot in an attempt to feel less lonely, says Primack. Or it might be that spending a lot of time on social media makes people feel isolated.

“You might watch all these interactions where it seems like everyone else is connecting,” he says. That could lead to feeling excluded. The images of other people’s seemingly perfect vacations, homes and lives, even though those are not likely to represent reality, can make you feel like you’re missing out.

It could be that influence goes both ways — isolation drives social media use and vice versa. Or there might be some unknown factor that is leading to both social isolation and social media use.

– Katherine Hobson

Read more: Feeling Lonely? Too Much Time On Social Media Might Be Why

Image by Marvin Meyer from Unsplash