Teenagers are getting more anxious and depressed because of the 24-hour demands of their social media accounts, researchers say.
Those with higher levels of emotional investment in social media, and who use it at night, were more likely to feel depressed and anxious, they say.
Glasgow University researchers questioned 467 teenagers about their use of social media and state of mind.
They found many felt a pressure to respond immediately to texts or posts.
Lead researcher Dr Heather Cleland Woods and Holly Scott asked the teenagers about how and when they used social media.
Sleep quality, self-esteem, anxiety, depression and the subjects' emotional investment in social media were also measured.
This related to the pressure to be available 24/7 and any anxiety around, for example, not responding immediately to texts or posts.