The stereotype of an internet addict is a nerdy young guy who spends all his time in front of some kind of online role-playing game.
However, the reality is more diverse, with recent studies showing plenty of young women are also at risk of internet addiction, primarily due to social networking sites like Facebook.
Just about all girls diagnosed with the addiction trace their problems to social networking sites, says Bernd Werner, from the German Foundation for Media and Online Addiction.
"They're always thinking about what's going on right now in the network," he says. They use such sites to chat with others in their clique.
"There's pressure from within the peer group."
The problem is that many parents have not yet tuned in to the addiction danger, warns Werner. They are more prone to sound the alarm when children - primarily boys - show signs of addiction.
The signs parents would note for online addiction are the same for girls on social networking sites as for boys involved in online gaming.
"For one thing, there's a loss of control," says Werner. "I can no longer control how long I stay on the internet."
The second indicator is a change in tolerance levels.
"I consciously tolerate the fact that my behaviour leads to stress with my parents or worsening marks at school."
The most serious sign is when a girl starts to ignore friends, hobbies or basic hygiene.
Statistically, internet addiction is more of a male problem.
One German study showed that 0.7 per cent of people aged 25 to 64 had trouble breaking away from games or social networks. Taking into account the whole population, about 1 per cent of men suffered from addiction, almost double the figure for women, at 0.4 per cent, the federal appointee for addiction issues, Mechthild Dyckmans, reported.
The job of monitoring a child's internet usage is made easier if the computer is not set up in their room.
"Instead, put it somewhere where parents often walk by," recommends Werner.
"It's also not a good idea to allow boys and girls to have their own smartphones too early, regardless of protestations that 'everyone else has one."'
Set computer usage time limits with your children and also take a real interest in what your daughter is doing on Facebook, says Werner.
Such topics can easily be discussed during family meals however Werner warns comments like "I don't like that" are best avoided by parents when it's time to discuss the matter, he says.