Isolation despite hyper-connectivity? The association between adolescents’ mental health and online behaviours in a large study of school-aged students

Abstract Smartphone use has risen rapidly amongst adolescents over the last decade, as has the rates of common mental disorders. This has raised widespread concerns about direct links between adolescents’ general screen time, social media use and their mental health. This study aimed to describe adolescents’ online behaviours (e.g., time spent on social media) and how that relates to anxiety, depression, and loneliness. In a sample of 14,726 adolescents (aged 12–16 years) using data from the OxWell 2021 student survey, Structural Equation Modelling (SEM) path analysis was conducted, exploring co-occurring associations between self-reported anxiety and depression symptoms (RCADS-25), loneliness (UCLA-SF3), and various screentime related activities. Moderation analyses per gender, age, and self-harm history were also conducted. Greater social media use was related to higher exposure to self-harm content online, seeking help online, regretting posting content online, meeting online strangers, frequency of social media use before sleep, and lower exposure to school night screen rules. Furthermore, exposure to self-harm content, seeking help online, and posting content online that was later regretted, in turn, related to higher anxiety, depression, and loneliness scores. Weak direct links between time spent on social media and anxiety and depression symptoms and loneliness were further moderated by age and self-harm history, respectively. These results suggest that what adolescents do online, rather than how much time they spend on social media, relate to anxiety and depression symptoms and loneliness. Although this study cannot infer the cause or direction of the examined associations, it highlights the importance of better understanding the context and content of social media use.