Greg Hartwell , clinical assistant professor 1 , Maeve Gill , specialty registrar in public health 2 , Marco Zenone , research associate 3 , Martin McKee , professor of European public health 1 1London School of Hygiene and Tropical Medicine, London, UK 2Royal Free Hospital NHS Foundation Trust, London, UK 3Health Law Institute, University of Alberta, Canada Correspondence to: G Hartwell gregory.hartwell@lshtm.ac.ukA precautionary public health response is neededThe tragic deaths of two UK teenagers continue to raise debate about the challenges that smartphones—and the unlimited access to social media they provide—may pose for adolescent mental health.1 Molly Russell took her own life in 2017 aged 14 after being exposed on Instagram to what her father has described as a constant stream of “dark harmful material.”1 Sixteen year old Brianna Ghey was murdered by two fellow pupils in 2023. Her mother believes that Brianna’s heavy mobile phone use increased her vulnerability before her death, and recently called for alerts on parents’ phones when their children use their own devices to search for violent material, as her daughter’s killers did.12This debate lies within broader concerns about the parlous state of adolescent mental health, with decreasing happiness reported among UK teenagers for a decade, alongside sharp increases in depression and anxiety, particularly among older girls.34 These findings cannot easily be dismissed as artefact arising from changes to diagnostic criteria, reduced stigma, or greater willingness to seek help; …
