Children who use social media for more than three hours per day are more likely to develop greater levels of depression and anxiety compared to those who use it more moderately.
The findings are the latest analysis to come from the SCAMP study, led by public health researchers at Imperial College London and based on data from more than 2300 children in schools across London.
They show that children in Year 7 (aged 11-12) who used social media sites for more than three hours per day were more likely to have developed symptoms of depression and anxiety by the time they reached Year 9 and Year 10 (aged 13-15), with girls having a stronger link between their usage and depression compared to boys.
The research shows the effects are mainly driven by disruptions to sleep – with greater social media use, especially into the evenings, reducing children's amount of sleep which, in turn, results in lasting impacts on their mental health.
According to the team, their analysis suggests that while social media use by itself may not necessarily be causing harms, there is a pattern linked with excess use. The researchers say that promoting moderate use and better sleep hygiene could help to achieve a better life balance and reduce the potential mental health impacts.
The researchers caution the digital landscape has changed dramatically since their data were collected in 2014-2018 (including consumption levels and the type of content on platforms, such as short form video), and recommend that further research using more recent and detailed data is needed. The study is published in the journal BMC Medicine.
Dr Chen Shen, from the School of Public Health at Imperial and first author of the study, said: "The relationship we see is complex, so it's not as straightforward as saying that social media use directly causes poor mental health in children, like the well-established direct link between smoking and lung cancer, for example. But we see that children who use social media above a certain level when they are in Year 7 are more likely to develop mental health problems when they reach Years 9 and 10, and we believe this is largely due to sustained disruptions to sleep.
"We know social media platforms have changed enormously over the last decade and are likely to change as much if not more in the next 5-10 years. As the platforms, usage and content evolve, we need continued research to understand how social media use affects children's mental health in today's digital environment."
Professor Mireille Toledano, Mohn Chair in Child Health at Imperial's School of Public Health, and Principal Investigator of SCAMP, said: "Our analysis shows a clear trend in terms of the amount of time spent on social media and mental health outcomes. Children who use social media apps for longer, and later into the evening, may be offsetting the sleep they need to function healthily. We think this is the key reason we're seeing a lasting impact on their mental health down the line.
"There seems to be growing support for a total ban on social media use for under-16s, and for the current non statutory guidance of no phones in schools to become a legal ban. But at the moment, we don't actually have the evidence to support these bans or claims that social media or mobile phone usage are harmful in themselves. The picture is complex and multi-factorial and we need to better tease out what is driving the associations we see. The SCAMP study with its rich dataset on physical and mental health, cognitive function, physical activity, sleep, diet, genetics, and puberty biomarkers is facilitating just this. For example, our study provides evidence that the link between social media use and depression and anxiety is largely driven by offsetting healthy behaviours - like getting enough sleep."
Changing landscape
The latest findings come amidst moves to ban social media for under 16s in Australia and Spain, as well as an active debate on a ban for school-aged children in the UK. Critics claim that social media use and exposure to online content is potentially damaging for children. But to date the population level evidence of whether exposure to social media is directly linked to health harms has been limited.
The prospective longitudinal Study of Cognition, Adolescents, and Mobile Phones (SCAMP) was set up in 2014 as the largest study of its kind to investigate the use of mobile phones in relation to cognitive, behavioural and mental health outcomes in adolescents. Previous SCAMP publications have shown links between various patterns of digital technology use (e.g., night time use, social media use, video gaming) and poor sleep, behavioural difficulties, lower wellbeing, and obesity in young adolescents (aged 11-12).
In the latest analysis, researchers looked at data from 31 schools from across London, with baseline data collected when children were in Year 7 (aged 11-12) and then again when they were in Year 9 and Year 10 (13-15). Baseline data from Year 7s were collected from 2014-2016, with follow up data collected from 2016-2018. Data collection included a detailed questionnaire on digital technology behaviours, mental health, health and lifestyle, as well as a battery of cognitive tests. A total of 2,350 children were included in this analysis.
Researchers found that compared to limited use of up to 30 minutes per day, more than 3 hours of social media use per day at baseline was associated with greater severity levels of depressive and anxiety symptoms and clinically significant symptoms at follow-up. The link between social media use and depressive symptom severity was stronger in girls than boys, but other associations were similar by gender.
Analysis revealed that an insufficient amount of sleep, particularly on school nights, and going to sleep later mediated the associations of social media use and depressive and anxiety symptoms. The role of sleep disruption – such as from phone alerts – was found to be less pronounced but still significant.
Next Steps
The researchers are now carrying out an intervention study in multiple schools to trial an education programme (called 'Scroll Smart') to teach children how to moderate their social media use and the importance of sleep hygiene.
Two schools will deliver workshops to students on social media use, while two schools will act as the control group for comparison, with children followed up at further time points to show any effects of the intervention. It is hoped that the analysis will provide further findings in the coming months.
The authors highlight several limitations to their analysis, including the historical data collection period. There are also issues around collecting accurate usage of data, as well as a lack of detail on the type of content consumed.
However, unlike many surveys using cross-sectional data, this SCAMP longitudinal analysis is able to rule out the bi-directional nature of the relationship – i.e. whether more screen time means more depression and anxiety, or that those who are more depressed, anxious or withdrawn are more likely to spend more time on their phones. Participants' mental health at baseline when they are 11 years old is captured and then taken into account in their follow up analyses.
Professor Toledano added: "We know that high levels of mobile phone use and screen time are offsetting physical activity, impacting our sleep and affecting obesity and mental health. Whether it's overuse, late night use, 'doomscrolling' or 'phubbing', our phones are the conduit and pushing away some of the other factors which are very important for healthy living. If we can educate young people to use their phones in a more balanced way, we may not necessarily see social media use or phone use more generally as a problem to ban."
UK government debates ban
Earlier this month (2 March), the UK government launched a consultation on children's social media use, which includes potential age restrictions on social media and other services, and better support for parents and families.
Commenting on the consultation, Professor Toledano said: "We've already seen Australia move to implement a social media ban for under 16s, and European countries including France, Spain and Greece all looking to implement restrictions and age verification measures this year due to child safety concerns.
"While measures to restrict children's exposure to potentially harmful online content are necessary and should be welcomed, currently there just isn't enough scientific evidence to suggest that social media use by itself is harmful for children. Despite calls for an outright ban for under 16s, the evidence that this will solve all the issues children are facing just isn't there.
"Our recent work showed extended social media use was linked with poor mental health, but this is likely to be indirect and related to pushing usage into the evenings which disrupts sleep. Over the medium to long term, sleep disruption can have profound implications for children's mental health and wellbeing, and their school performance.
"Some of the suggested measures being explored in the government's consultation, such as overnight curfews and helping children and parents to better navigate digital spaces, could help to reinforce healthier habits and reduce associated harms we see reported.
"The best outcome may be better regulation of the content and working with children and parents to educate them about healthier use. Instead of the UK jumping on an arbitrary ban, it might be prudent to see what happens in Australia over the course of this year and the impacts of the ban on young people's health and wellbeing."
SCAMP is funded by the Medical Research Council (MRC) and originally commissioned and funded by the National Institute for Health and Care Research (NIHR) and the Department of Health and Social Care. The study is also supported by the NIHR Health Protection Research Units in Radiation Threats and Hazards (RTH) and Chemical and Radiation Threats and Hazards (CRTH). Infrastructure support was provided by the NIHR Imperial Biomedical Research Centre. Professor Toledano is supported by the Mohn Centre for Children's Health and Wellbeing at Imperial College London.
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'Social networking site use, depressive and anxiety symptoms in adolescents: evidence from a longitudinal cohort study (SCAMP)' by Shen, C., Girela-Serrano, B.M., Di Simplicio, M. et al. is published in BMC Medicine.
DOI: https://doi.org/10.1186/s12916-026-04667-5
