HAMBURG: Whether TikTok, Instagram and other platforms are as dangerous as alcohol or tobacco is a question now putting Meta and Google on trial in the United States, putting TikTok under pressure in the EU and being debated by governments around the world.
Researchers have long examined what happens when children and teenagers spend large parts of their day working their way through bottomless timelines. Here are some of the most important findings on doomscrolling.
How much time do teens spend on their phones?
The short answer: a lot. Various studies have pointed to teens spending two and a half to four hours on their smartphones every day.
In simple terms, time spent scrolling on TikTok is time not spent doing sport, playing an instrument or having uninterrupted conversations with friends. The more time goes into social media, the less remains for other things, not least sleep.
In a study by German educational research association MPFS, around 30% of teenagers reported often being tired in the morning because they stayed on their phones too long at night.
A Dutch longitudinal study published in the journal Communication Research in 2021 found that 28% of teenagers surveyed said their well-being worsened through social media use, while 26% reported improvements.
However, the answer is more complex. It is now well evidenced that increased use of social media and smartphones, as well as problematic use in the sense of addiction-like behaviour, is associated with lower mental well-being, more sleep problems, more depression, more eating disorders and more self-harm, says youth psychologist Isabel Brandhorst, who leads a research group on internet addiction.
However, she said longitudinal studies are less clear on causality.
Sven Lindberg, professor of developmental psychology at Germany's University of Paderborn, pointed out that while the link between social media use and mental health problems is fairly well researched, the significant effects are small and mainly affect certain vulnerable groups.
"That means it does not affect the majority, it is not the norm, but it affects individual vulnerable groups and for them that is of course a problem."
Who is most at risk?
Children and teenagers who already face other burdens are especially at risk, Lindberg said. If a person is already anxious or has a depressive disorder, using social media can amplify these effects.
One at-risk group is girls, he said, because social comparisons play a large role. "That means that if I am unhappy with my self-image, social media will probably make me even more unhappy because I'm comparing myself."
Brandhorst also worries about adolescent girls. She said they have a slightly higher propensity to addiction but hardly appear in counselling centres and therapy services.
"There we actually have only male computer gamers, who are practically dragged by the scruff of the neck by their parents into counselling centres."
Another group is victims of bullying, according to Lindberg. "Cyberbullying on social media and the like has a much stronger effect, because I am not only teased in the playground but 24/7."
When does it become dangerous?
Parents like to know how many hours are too many. That is not easy to answer. "Studies show that sheer time spent is not the problem. It very much depends on what is being done," Lindberg explained.
"As a rule of thumb: the more passive the use is, just scrolling and scrolling, the more negative it is." Someone could use social media for eight hours a day and not suffer because it is linked to their job, he said.
"But it can also be that someone uses social media for three hours, but actually thinks the whole time that they would rather be doing something else. Then those three hours are already problematic because it is experienced as unwanted on an individual level."
About one in four teenagers aged 10 to 17 uses social media in a way classified as problematic, and almost 5% are considered dependent, according to a 2025 study in Germany by researchers at University Medical Center Hamburg-Eppendorf and insurer DAK.
That was a slight decline compared to the previous year, but still clearly above the pre-pandemic level.
Lindberg said the threshold for addiction needs to be defined, and that the same rules apply as with other addictions. "If someone is addicted, then they suffer from the fact that they cannot do otherwise than they actually want. And that it restricts them, for example in their work or in their social contacts."
What do teenagers themselves say?
In the JIM study, respondents were self-critical: a majority (68%) fully or largely agreed that they often spend more time on their phones than originally planned. A similar share enjoys spending time without a phone and the internet. Brandhorst also emphasised that some teenagers reflect on their own use and consciously limit it. But: "It requires a lot of capacity for reflection and self-control, and many teenagers simply do not have that."
Brandhorst nevertheless sees positive effects: teenagers can try out identities, find like-minded people and talk about topics that may carry shame.
Lindberg emphasised that the vast majority of teenagers show no problematic behaviour.
"You might have the impression that this affects the majority, but in fact the majority shows no clinically relevant problematic behaviour; those affected are rather a minority, on a scale similar to other problematic behaviours." – dpa
