Why girls are more affected

In girls, frequent social-media use seemed to harm health when it led to either cyberbullying and/or inadequate sleep and exercise. 

But these factors did not seem to have the same effect on boys, and the study didn’t pick up on specific ways that social networks could be harming them.

The message, really, is that it’s not social-media use, per se, that causes harm,” says study co-author Dasha Nicholls, who leads the Child and Adolescent Mental Health research team at Imperial College London. 

“It’s about getting a balance between social-media use and other age-appropriate ac...