Letter to the Editor: Do smartphone bans improve adolescent mental health? Limitations of cross‐sectional evidence

The growing concern about the impact of smartphone use on adolescent mental health has led to increasing policy interest in school-based smartphone bans. A recent cross-sectional study by Sullivan and colleagues, examining digital safeguarding incidents in schools with and without smartphone restriction policies, contributes to this debate. However, caution is needed when interpreting these findings as evidence of mental health benefits. Cross-sectional designs inherently limit causal inference, as schools adopting smartphone restrictions may differ systematically in institutional resources, monitoring practices, and student populations. Higher reported safeguarding incidents in schools with restrictions may therefore reflect greater detection sensitivity rather than increased underlying harm. Furthermore, digital safeguarding incidents are not direct indicators of psychological well-being, but are shaped by reporting practices and institutional thresholds. Population-level research suggests that associations between smartphone use and mental health are modest and context-dependent. While school-based restrictions may reduce in-school phone use, there is little evidence that they reduce overall screen time or improve mental health outcomes. Future longitudinal and quasi-experimental studies directly assessing psychological outcomes are needed. Until such evidence is available, caution is warranted in promoting smartphone restriction policies as effective mental health interventions.