Maartje Boer

SMU AND WELLBEING ACROSS COUNTRIES 123 4 using more specific and objective measures of SMU, such as smartphone application tracking apps, are important directions for future research. Conclusion Notwithstanding the previously mentioned limitations, the finding that adolescents throughout 29 countries who report problematic SMU are particularly at risk for impairments in wellbeing, is highly relevant to current policies and guidelines for healthy SMU. Schools, family, and clinical settings are potential contexts for the detection of adolescents with problematic SMU, as well as for the implementation of support and interventions aimed at reducing the levels of problematic SMU. Additional support may be provided to adolescents reporting intense SMU in countries with a low prevalence of intense SMU, because they may also be vulnerable to lower wellbeing.