Summary: New, population-level evidence links high social media use to later declines in adolescent mental health. The Child to Adult Transition Study (CATS) in Melbourne tracked nearly 1,200 participants from age 9 through 19 and found that spending two or more hours per day on social platforms predicts small but measurable increases in depressive symptoms and reduced subjective well-being one year later.
An international research collaboration found that adolescents who averaged two or more hours of daily social media use faced a higher likelihood of elevated depressive symptoms and poorer well-being at the next annual assessment. The effect was strongest in early adolescence and was particularly pronounced for girls aged 12–13, highlighting a sensitive developmental window.
Key Facts
- Ten-year population cohort: This study followed a population-based cohort of 1,153 children over ten years, collecting yearly measures of social media use, depression, anxiety, well-being, and self-harm from ages 9 to 19.
- Two-hour threshold: Adolescents averaging two or more hours of daily social media use showed systematic increases in depressive symptoms and declines in well-being one year later compared with peers who used social media for less than one hour per day.
- Early adolescence is a sensitive period: The negative associations between social media use and mental health were most evident during early adolescence (ages 12–13), a time of rapid pubertal brain changes and heightened sensitivity to peer evaluation.
- Girls at highest risk: Within this vulnerable early-adolescent period, girls aged 12–13 exhibited the most pronounced increases in depressive symptoms associated with higher social media use.
- Population-level implications: Although individual effect sizes are modest, the public health impact is substantial because social media exposure is widespread; even small increases in risk can lead to significant demands on clinical and support services.
- Baseline for policy evaluation: The data represent youth mental health patterns before Australia’s social media age restrictions and form a foundation for the Connected Minds Study, which will evaluate changes after the introduction of stricter age gates on December 10, 2025.
- Balanced prevention approach: While social media can support identity development and peer belonging, risks such as cyberbullying, harmful content, and toxic comparison require multi-layered preventive strategies including age-appropriate limits, digital literacy education, and parental guidance.
Source: Murdoch Children’s Research Institute
Headline finding: Adolescents who spend at least two hours a day on social media are more likely to report depressive symptoms and lower well-being one year later, with the strongest associations observed in early adolescence.
Led by the Murdoch Children’s Research Institute (MCRI), this decade-long study examined social media use and subsequent mental health outcomes for young people aged 9–19. The researchers collected annual data on social media habits and validated measures of depression, anxiety, well-being and self-harm, offering one of the most complete longitudinal pictures of screen time and adolescent mental health to date.
Published in The Medical Journal of Australia, the analysis showed that adolescents who used social media for at least two hours daily had a higher probability of elevated depressive symptoms and poorer subjective well-being at the next yearly assessment compared with peers using social media for under one hour. The most marked effects were found in girls aged 12–13.
Dr Nandi Vijayakumar (MCRI and Deakin University) said the results underscore early adolescence as a critical window for intervention. “Early adolescence stands out as a period when higher social media use is linked to a greater risk of mental health problems one year on,” she said. “Although the increases in risk are modest, small effects at the population level can have substantial public health consequences, which is why early intervention matters.”
Professor Susan Sawyer (MCRI) emphasized the need for balanced policy responses. “Our findings help move the conversation beyond anecdotes to population-level evidence,” she said. “Social media can offer social connection and creative expression, but it also carries risks that call for age-appropriate limits, improved digital literacy education, and clear guidance for families and schools.”
Previous research by MCRI has highlighted high rates of clinically significant depression and anxiety symptoms among Australian adolescents, reinforcing the need for preventive strategies alongside clinical care. MCRI and Deakin University are continuing to monitor the impacts of Australia’s social media age restrictions through the Connected Minds Study, which follows 13–16-year-olds and their parents as policy changes come into effect.
The research team included investigators from The Royal Children’s Hospital, the University of Melbourne, UCL Great Ormond Street Institute of Child Health, Imperial College London, London North West University Healthcare NHS Trust, the University of Bristol, the University of Oxford and Curtin University.
Key Questions Answered:
A: Prolonged exposure to social media can alter social development. Platforms often promote constant social comparison, idealized images of peers, and opportunities for cyberbullying. For vulnerable adolescents, two or more hours a day absorbing these messages can undermine self-esteem, increase stress, and contribute to the gradual emergence of depressive symptoms over time.
A: Early adolescence is marked by rapid biological and social changes. At ages 12–13, many girls are undergoing intense pubertal brain development and heightened sensitivity to social status and peer acceptance. These developmental factors can make them more susceptible to the negative social signals and validation cycles common on image-focused platforms.
A: The study does not argue for outright bans. Instead, it supports a measured approach: recognizing benefits such as social connection and creative expression while reducing harms through age-appropriate limits, digital literacy education, and active parental and school engagement to protect young people during vulnerable developmental stages.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional contextual details were added by editorial staff.
About this social media and teen depression research news
Author: Bridie Byrne
Source: Murdoch Children’s Research Institute
Contact: Bridie Byrne – Murdoch Children’s Research Institute
Image: Image credit: Neuroscience News
Original Research: Findings published in The Medical Journal of Australia