"This is obviously scary," psychologist Ingrid Gråberg tells newspaper Dagens Nyheter. "Self-confidence is connected to all of this. A desire to be popular is what connects most of this behavior and it's not a new phenomenon."
Gråberg says parents should build up their children's confidence long before they become teenagers. She says parents need to listen and respect their children's wishes.
Twenty-two percent of the teenagers uploaded photos or videos of themselves because they wanted comments about how they look.
"Affirmation in itself isn't dangerous but it's not so good if you become very dependent on it and do virtually anything to get affirmed," says Gråberg.
The online poll had 1,009 participants between the ages of 15 and 24.