The last thing they do before going to sleep is to quickly check the social networks on the smartphone. And the first waking moment also belongs to the device, when the user reconnects to the "outside world."
A day without social networks often triggers symptoms of withdrawal. Several studies have found that users cut off from their digital connection suffer restlessness and nervousness. Many people fear that a new wave of addiction could be about to hit society.
In terms of kids, typical signs of online addiction include if they become unruly, don't get up on time or don't wash or get to school on time, according to Marlene Mortler, Germany's commissioner on drug abuse.
At the same time there may be frequent truancy and poor school grades and the children or young people may struggle with sleep problems. In the case of computer game addicts, psychological disorders including depression have been observed.
But what's the solution?
"Shaming them doesn't help," says Mortler. It is necessary to deal with the children and their problems in a positive way. If that doesn't work, parents should seek professional advice.
Part of the problem is that for many parents, it's hard to establish rules for the use of computer games and the internet because the parents, unlike their kids, they weren't born into the world of the internet.
There are also gender differences, Mortler says. Girls are more likely to become addicted to social networks, while for boys it's more likely to be computer games. Players of online role-playing games or strategy games are particularly vulnerable.
And even though internet addiction can affect children and young people of all social classes, it seems those with poor social skills or who are the offspring of single parents seem particularly at risk.