Children as young as nine are so dependent on their cellphones they check them day and night, research in Britain has found.
The study into children's technology usage was the first of its kind in the UK and involved students in both state and private schools.
It found that 45 percent of 11- to 18-year-olds admitted checking their social media accounts when they should have been sleeping.
The survey of 2750 people from the 11-18 age group found one in 10 admitted checking at least 10 times a night.
They said they were happy to risk turning up for school tired and unable to concentrate to look at their night-time notifications.
About 68 percent admitted using a mobile at night was affecting their school work, while a quarter admitted to feeling tired during the day because of it.
In total, 94 percent of the group were using social media and, of those, about 10 percent said they would feel stressed about missing out if they did not check their device before going to sleep.
Of those who checked their phones after going to bed, about 32 percent said their parents were unaware they were doing so.
The poll was carried out by Digital Awareness UK (DAUK) and the Headmasters' and Headmistresses' Conference (HMC).
Charlotte Robertson, DAUK co-founder, said: "One of the biggest topics around at the moment is excessive social media consumption and how it is affecting our physical and emotional well-being.
"A lot of them [children] are waking up sometimes with over 100 notifications from conversations that have happened overnight.
"They want to be that person that is responding at 1.00am, 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."
HMC chairman Mike Buchanan said: "The data suggests those who do check their phones, they're mostly driven by not wishing to miss out.
"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."