Children as young as nine check their mobile phones at least 10 times a night because of the "fear of missing out", researchers have found.
Many pupils told researchers they risk turning up for school tired and unable to concentrate due to looking at notifications from their mobile devices while in bed.
One in 10 of those polled said they checked their phones at least 10 times a night.
Almost 50% of 11 to 18-year-olds admitted checking social media accounts such as Snapchat, Facebook and YouTube when they should be sleeping.
Charlotte Robertson from Digital Awareness UK, who worked on the survey, said: "The youngest (child checking their devices at least 10 times a night) is about nine, and many parents are very unaware of it.
"A lot of them are waking up sometimes with over 100 notifications from conversations that have happened overnight.
"They want to be that person that is responding at 1am, and seen to be quite cool, to make sure they catch the joke - it's a huge driver, that anxiety of wanting to know what's happened."
The chairman of the Headmasters' and Headmistresses' Conference, where the results were discussed, said most children were driven by a fear of missing out.
Mike Buchanan said: "Clearly there are some times when children are not concentrating because they are tired, and that has an obvious impact on their ability to keep up with what's going on - there is a desire to stay within the group.
"It's not that this (technology) is all horrible and terrible and that we should all be wringing our hands.
"It is more a case that here's the reality, let's use it and try to influence the use of technology in a positive way."