New studies from Canada and Australia link more time on social media to higher rates of depression in teenagers, with the clearest signals in girls aged 12 and 13. Both countries are writing age limits into law, and health bodies set out steps families and schools can take now.
If you’re deciding when a daughter should open her first social media account, two large studies published this year point to the early teens as the time to watch. In Melbourne, researchers found the largest links with depression in girls aged 12 and 13. In Canada, a study of more than 58,000 teenagers found links with depression and anxiety at every age, strongest in girls.
Australia already enforces an under-16 limit on social media accounts, and Canada is debating one. Both new studies are observational. They show associations between use and mental health, and they can’t prove that social media causes the problems. However, they track large groups of young people over time, which gives them more weight than one-off surveys.
Girls aged 12 and 13 show the largest effect
The Medical Journal of Australia study followed 1,195 young people in Melbourne, recruited from schools in 2012. Nandita Vijayakumar and colleagues linked daily social media use at each age from 12 to 18 to mental health one year later.
Among girls aged 12 and 13, more than two hours a day, compared with less than one hour, was linked to 10.8 more cases of high depressive symptoms per 100. The risk ratio was 1.72. Even one to two hours a day was linked to poorer wellbeing at that age.
Across all ages, heavy use was linked to 6.7 more cases of high depressive symptoms per 100 girls, a risk ratio of 1.22. It was also linked to 6.5 more cases of poor wellbeing per 100 girls. Links with anxiety in girls were close to zero.
Boys showed different patterns, mainly in anxiety and self-harm, though the estimates were less certain. Across both sexes, risks were roughly half as large in later teenage years. The authors concluded that early adolescence “may represent a key developmental period” for policies to reduce heavy use.
Each extra hour, across five Canadian provinces
The University of Alberta study, released in September, drew on COMPASS, a school-based health study in British Columbia, Alberta, Ontario, Prince Edward Island and Quebec. Researchers analysed more than 58,000 teenagers aged 12 to 18 in the 2021 to 2022 school year. They analysed nearly 45,000 in 2022 to 2023, and followed nearly 27,000 of the same young people from one year to the next.
Each extra hour of daily use was linked to a 15% higher chance of moderate to severe depression. It was also linked to a 12% to 13% higher chance of moderate to severe anxiety. Higher use was tied to lower wellbeing, poorer emotional control and weaker relationships.
Madelyn Curle led the study as part of her PhD. “There is evidence that girls may use social media more intensively than boys,” she said. The release does not report separate figures for girls, and it notes that future work should look at which apps teenagers use and whether they post or scroll.
Teenagers whose use rose from one year to the next had poorer mental health a year later. In that year-on-year analysis, the researchers found no difference between girls and boys.
Europe’s survey of 44 countries
The WHO Regional Office for Europe found a similar pattern in its Health Behaviour in School-aged Children survey. It reported in 2024 that problematic social media use rose from 7% of adolescents in 2018 to 11% in 2022. The survey covered about 280,000 young people aged 11, 13 and 15 in 44 countries and regions, including Canada. Problematic use was higher in girls, at 13%, than in boys, at 9%. These are the latest available figures.
Australia and Canada set the line at 16
Australia’s minimum age law took effect on 10 December 2025. It requires age-restricted platforms to take reasonable steps to stop under-16s holding accounts. The duty sits with the platforms, which face fines of up to A$49.5 million, the Department of Infrastructure says. Australia’s eSafety Commissioner began an evaluation of the law’s effects on children in February 2026.
Canada’s government introduced Bill C-34, the Safe Social Media Act, on 10 June 2026. It would prevent children under 16 from holding social media accounts. Platforms could seek an exemption by showing they have sufficient safeguards for children. The bill needs approval from both the House of Commons and the Senate, a legal overview by LawNow explains. Valerie Carson, who co-led the Alberta study, said its results support the proposed law.
UNICEF Canada welcomed the bill but questioned blanket bans. “Countries with only a blanket age ban in place, like Australia, are finding them extremely difficult to enforce and unevenly applied,” said Sevaun Palvetzian, its president and chief executive, in a statement. UNICEF Canada wants young people consulted, a well-funded regulator and a child rights impact assessment.
Curle also called for youth input in policy. She noted that social media can give LGBTQIA+ teenagers connection, identity development and social support.
Steps families and schools can take in the early teens
The American Psychological Association’s health advisory, issued in the US in 2023, advises adults to review, discuss and coach teenagers’ use. It says this is most important between ages 10 and 14, with more independence given as children grow. Social media should not cut into sleep or physical activity, the advisory says, and use in the hour before bed is a particular concern.
The APA also advises teenagers to limit using social media to compare themselves with others. It links that kind of comparison to poorer body image, disordered eating and depression, particularly in girls.
The Melbourne authors said limits on use would need support alongside them, such as parental guidance, media literacy teaching in schools and safeguards built into platforms. The WHO Regional Office for Europe calls for digital literacy teaching in schools, better mental health services and stronger platform accountability.
Carson drew one practical lesson from the year-on-year results for teenagers who already use social media heavily. “Our findings suggest that decreasing social media use over time may support better mental health outcomes among adolescents,” she said.
Anyone affected by the issues in this article can find support through Child Helpline International, which lists free helplines for children and young people by country.
This article is for information only and does not replace advice from a qualified health professional.
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