Debate: Social media in children and young people - time for a ban? From polarised debate to precautionary action - a population mental health perspective on social media and youth well-being.

Adolescents spend much of their daily lives online, with social media a central part of their digital environment. While findings are complex, evidence increasingly points to small but relatively consistent harms, particularly for those meeting criteria for problematic use. At the population level, these effects are concerning, given the extraordinary prevalence of exposure to social media, rising rates of problematic use and adolescents' vulnerability to mental ill-health. The complexity of determining causality should not delay action: from a public health perspective, precautionary measures are warranted. We argue for a comprehensive approach that includes effective age verification and age-appropriate protection, regulation of harmful design features for all ages and inclusion of young people's voices. Just as offline environments include regulation and guidance, digital environments must be shaped to support individual and community needs.