For some, the final half-hour of the day means one last scroll through TikTok or catching up on your favourite TV show.
But a new study involving more than 45,000 university students suggests that any screen time after lights-out, no matter the activity, is linked to poorer sleep.
Published in Frontiers in Psychiatry, the research from the Norwegian Institute of Public Health challenges the long-held belief that social media is uniquely damaging to sleep. Instead, it finds that the total amount of time spent using screens in bed is the key issue, not the type of content being consumed.
Is it time you ditched your phone in bed?
Sleep quality and duration have been steadily declining in young adults, particularly among students. Numerous studies have linked digital media use with sleep disturbances, yet most of the existing literature focuses on adolescents, with little attention paid to university students and young adults. As smartphones and other digital devices become near-permanent fixtures in evening routines, understanding their true impact on sleep is increasingly important.
While past research has often singled out social media as a particularly disruptive activity, evidence has been inconsistent. Some studies have suggested that the interactive and emotionally engaging nature of social platforms increases cognitive arousal, while others have posited that the social connection it provides could be protective. This new study addresses this ambiguity by directly comparing social media use to other screen activities such as watching TV series, reading study material, or gaming.
Study Overview: The SHOT2022 Survey
The research, led by Gunnhild Johnsen Hjetland and colleagues at the Norwegian Institute of Public Health, utilised data from the SHOT2022 survey (Students’ Health and Wellbeing Study). This national cross-sectional study collected responses from full-time students aged 18 to 28, focusing on health behaviours, screen use, and sleep patterns.
Of the 169,572 students invited to participate, 59,544 completed the web-based questionnaire, with a final sample size of 45,654 participants used for the main analyses. Participants were asked to report how frequently and for how long they used electronic devices in bed after going to sleep, as well as which activities they engaged in.
Screen-based activities were grouped into three categories:
Social media use only
Social media use in combination with other activities
Non-social media screen use (e.g., streaming, gaming, study-related content)
The analysis also accounted for insomnia symptoms, measured according to DSM-5 criteria, and self-reported sleep duration.
Key Findings: Time Spent on Screens Matters Most
The clearest pattern to emerge from the study was the strong association between screen time in bed and poorer sleep outcomes, regardless of the activity type. Each additional hour of screen use in bed was linked to:
A 59 percent increase in the odds of experiencing insomnia symptoms
A 24-minute reduction in total sleep duration
These findings held steady across all types of screen activity, suggesting that it is the amount of time spent using screens in bed—rather than the specific content consumed—that has the greatest impact on sleep health.
Social Media: Surprisingly Less Harmful Than Expected
Contrary to widely held assumptions, students who only used social media in bed experienced better sleep outcomes than those who used other types of screen-based media. Specifically:
The social media-only group had the lowest rates of insomnia (27.6 percent)
They also reported the longest average sleep duration (7.76 hours)
"We found no significant differences between social media and other screen activities, suggesting that screen use itself is the key factor in sleep disruption." said Dr Gunnhild Johnsen Hjetland of the Norwegian Institute of Public Health
In comparison, students who avoided social media but used screens for other purposes had the shortest sleep duration (7.38 hours) and the highest rates of insomnia (37.1 percent).
Those who used social media alongside other activities fell between the two extremes.
These findings challenge the idea that social media is uniquely disruptive. The authors propose several possible explanations:
Social media use may reflect active social engagement, which is known to support mental well-being and sleep health.
Other screen activities, such as binge-watching or studying, may be more stimulating or time-consuming, leading to greater sleep disruption.
Some students may consciously avoid social media due to prior negative experiences or sleep issues, selecting alternative media that inadvertently cause more harm.
Mechanisms: Displacement Over Arousal or Light Exposure
The study lends support to the displacement hypothesis, which posits that screen use in bed delays sleep primarily by encroaching on time that would otherwise be spent sleeping.
While theories involving melatonin suppression (via blue light) and cognitive arousal are often cited, the uniformity of the findings across screen types suggests that time displacement may be the dominant mechanism.
This interpretation aligns with recent experimental literature, which shows minimal effects of light exposure and arousal on sleep when studied in isolation. Instead, the simple delay in bedtime—prolonged by engaging digital content—appears to be the most reliable predictor of shortened sleep.
Limitations of the Study
While the study is one of the largest of its kind and offers valuable insights, it does carry limitations:
It is cross-sectional and therefore cannot establish causality.
The data rely on self-report measures, which may be subject to recall bias.
The broad categorisation of screen activities may mask important differences within activity types (e.g., doomscrolling on social media versus passive browsing).
Notifications and overnight disruptions from smartphones were not assessed, though they are a known contributor to poor sleep.
Despite these limitations, the study is an important step forward in clarifying how screen habits affect sleep among young adults.
Implications for Sleep Health Recommendations
The findings suggest that blanket recommendations to avoid specific types of screen content (e.g., social media) may be misguided. Instead, public health messages should focus on:
Reducing total screen time in bed
Establishing consistent bedtimes
Using screens intentionally and avoiding prolonged, passive consumption
Turning off notifications and placing devices out of reach after bedtime
It is also worth considering individual differences. Some students may find that certain types of screen content (e.g., calming music or light social interaction) help them unwind, while others may experience heightened stimulation. Future sleep hygiene guidance should aim to be more personalised rather than universally prescriptive.
Areas for Future Research
Further investigation is needed to:
Explore the impact of specific screen behaviours and content types
Examine the role of overnight interruptions and device notifications
Evaluate longitudinal patterns to better understand causality
Understand cultural differences in screen use and sleep behaviour
Notably, previous studies have indicated that the impact of digital media on sleep may be stronger in Eastern populations than in Western ones, suggesting that cultural norms and expectations could moderate these associations.
Conclusion
This large-scale study of Norwegian university students offers compelling evidence that screen use in bed is associated with poorer sleep, regardless of whether the activity is social media, entertainment, or academic work. Importantly, the study challenges assumptions that social media is uniquely harmful and instead highlights the broader impact of total screen time.
As sleep continues to decline among young adults, particularly students, interventions aimed at reducing screen exposure after bedtime could prove beneficial. However, nuance is required: not all screen time is equal, and individual differences in how technology is used must be taken into account.
Going forward, a balanced and evidence-based approach to managing digital habits will be key to supporting better sleep health in modern life.
Citation: Hjetland GJ, Skogen JC, Hysing M, Gradisar M, Sivertsen B (2025). How and when screens are used: comparing different screen activities and sleep in Norwegian university students. Frontiers in Psychiatry. 16:1548273. https://doi.org/10.3389/fpsyt.2025.1548273
Comentarios