The survey of over 10,000 young people aged 12 to 20 suggests that cyber-bullying is widespread online.
Nearly 70 per cent of youngsters admitted to being abusive towards another person on social networks and 17 per cent claimed to have been bullied online.
One in three said they lived in fear of cyber-bullying, with appearance cited as the most likely topic for abuse.
According to the survey by anti-bullying charity Ditch the Label, 40 per cent participants felt bad if nobody liked their selfies and 35 per cent said their confidence was directly linked to the number of followers they had.
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Seven per cent of young social network users said they had been bullied on the Facebook-owned photo app.
That compared to a figure of 6 per cent for Facebook itself, 5 per cent for Snapchat and 2 per cent for Twitter.
Nearly half (47 per cent) said they would not discuss bad things in their lives on social media and many offered only an edited version of their lives.
"There is a trend towards people augmenting their personalities online and not showing the reality," said Ditch the Label's chief executive Liam Hackett.
The findings appear to contradict recent research from the Oxford Internet Institute (OII) that suggested cyber- bullying was relatively rare.
That research, which concentrated on 15-year-olds, found that, while 30 per cent reported regular bullying, only three per cent said it happened both off and online.