It begins innocently enough. A scroll through Instagram. A YouTube video. A quick reply to a friend. For millions of young adults, nighttime rituals now unfold not under lamplight or with a paperback, but under the hum of screens. But a new study from Norway suggests that nighttime device use in bed may come with a hidden cost: a disrupted night’s sleep.

Researchers studying more than 45,000 university students have found that using any kind of screen after going to bed — whether it’s for social media, gaming, or even listening to podcasts — significantly raises the risk of insomnia. Just one additional hour of screen time in bed increases that risk by 59% and shortens sleep by nearly half an hour.

Screen Time Displaces Sleep — But Not Equally

The researchers at the Norwegian Institute of Public Health enlisted 45,000 full-time university students, aged 18 to 28, and asked them questions about how often they used screens in bed and how well they slept.

Previous research often lumped screen use into one big category or focused on adolescents. But here, the team separated out activities — like watching TV, listening to music, gaming, studying, and social media use — and compared them.

More screen time in bed meant poorer sleep. For every hour students spent using screens after going to bed, their chances of reporting insomnia symptoms rose by 59%. And sleep duration dropped — on average — by 24 minutes.

But the main culprits were not what many might expect.

The researchers divided the students into three groups based on what they did in bed with their screens:

• Social Media only
• Social Media + other activities
• Non-social media users (TV, podcasts, studying, gaming, etc.)

Most students — about 69% — belonged to the mixed-use group. Around 15% used only social media, and another 15% avoided social media altogether.

It’s Not the Task, It’s the Duration

Contrary to the popular belief that social media is the worst offender, the study found that people who used only social media before sleep actually had the longest sleep duration and the lowest rates of insomnia.

After adjusting for age and sex, those who combined social media with other activities were 35% more likely to report insomnia than the social-media-only group. The non-social media group fared even worse, with a 71% higher likelihood of insomnia symptoms.

“The type of screen activity does not appear to matter as much as the overall time spent using screens in bed,” said Dr. Gunnhild Johnsen Hjetland of the Norwegian Institute of Public Health, lead author of the study published in Frontiers in Psychiatry.

Social media, though stimulating, might serve a comforting, even sleep-inducing, role. In contrast, those using technology to stream videos or listen to podcasts might be trying to fill the void of sleeplessness — using screens not to delay sleep, but to cope with their sleep pattern.

There’s a common assumption that social media is inherently bad for sleep. But this data suggests that how much time you spend on screens might be more important than what you’re doing.

So What’s Really Disrupting Sleep?

Four mechanisms are often cited when linking screens to poor sleep:

1. Displacement – screens simply eat into sleep time
2. Light exposure – blue light delays melatonin release
3. Arousal – mentally stimulating content keeps the brain awake
4. Notifications – alerts disrupt sleep after it begins

Of these, the new study lends the strongest support to displacement. If arousal or content were the key drivers, we’d expect different activities to show different effects. But they didn’t. All types of screen use showed similar patterns when it came to the trade-off between screen time and sleep.

That doesn’t mean arousal plays no role, especially in adolescents, whose brains are more reactive to social cues. But among young adults, time seems to be the dominant factor.

“If you struggle with sleep and suspect that screen time may be a factor, try to reduce screen use in bed, ideally stopping at least 30–60 minutes before sleep,” Hjetland advised. “If you do use screens, consider disabling notifications to minimize disruptions during the night.”

The study’s massive scale lends weight to its findings. But it’s still based on self-reported data, and that introduces uncertainty. Students might underestimate how long they use screens or misremember their sleep quality.

Moreover, the study took place in Norway. Cultural differences matter. A 2024 meta-analysis showed that the link between social media and sleep is stronger in Eastern than in Western cultures.

And critically, it can’t prove causality.

“This study cannot determine causality — for example, whether screen use causes insomnia or if students with insomnia use screens more,” said Hjetland.

Still, the sheer size of the survey — more than 45,000 students — makes it one of the most comprehensive looks yet at the link between screens and sleep in young adults. And while it doesn’t give us a neat villain in the form of a particular app or game, its findings are clear: the more time you spend on a screen after bedtime, the less rest you’re likely to get.