Social-media use and television time have been connected to depression in tweens and teens for a while now—but a new finding suggests not all screen time is a downer.

How: Researchers studied 3,826 adolescents entering seventh grade, almost evenly split between boys and girls, over the course of four years in the greater Montreal area. The study, led by Patricia Conrod at Université de Montréal and published in JAMA, looked at how self-reports of depressive behavior correlated with using four types of screens: computer, social media, television, and video games.

Isn’t that old news? Yes. But what’s surprising about the study is that it isolates video games as the one form of screen time that is neutral in its effects on teen depression. That could be because video games often don’t depict teens or people, Conrod said. Social media and television, on the other hand, may be associated with drops in self-esteem because of what Conrod called “images of idealized lives,” which lead kids to compare themselves with the glossy, filtered, unrealistic images they’re shown.

Another surprise: Conrod and her team found no evidence that screen time affected weekly physical activity. “This suggested to us that the relationship between television and social media on depression was mediated through content and thoughts, rather than physical activity,” she said.

Is there any type of screen time that is positive? According to Conrod, no.

What’s next? Plenty; this research is still in its infancy. Demographics—how gender, socioeconomics, and previous health factors might play a role in depression from screen time—need to be looked at more closely, Conrod said. Researchers also haven’t yet fully figured out what, exactly, it is about screen time that caused depression. Is it a specific type of image? Are there certain behaviors that put people at risk? Answering these questions won’t be easy, but it could help us live healthier lives.