Maartje Boer

CHAPTER 4 122 Finally, the finding that countries’ mobile internet accessibility did not explain differences in country-level prevalence of intense and problematic SMU suggests that a favourable internet access does not increase risks related to SMU. Cross-national differences in the prevalence of intense and problematic SMU may be better explained through countries’ prevailing cultural and social norms and rules regarding (social) media use, which may influence the extent to which schools and parents restrict adolescents’ SMU and educate adolescents in digital literacy. However, empirical research is required to verify this possible explanation. Strengths and Limitations The present study has important strengths related to the number of included countries, the representativenatureof thedata, and theconceptual distinction between intense and problematic SMU. However, our findings should be interpreted with caution, because mental, school, and social wellbeing were measuredusingeither singleorafewitems. Theuseof suchmeasuresmayhave limited the representations of the wellbeing constructs, and reliability could not be established for the single-item measures. Hence, more research that replicates our study using more detailed measures of wellbeing is warranted. In addition, the cross-sectional design of the study does not allow for causal inferences. A reverse pattern whereby low wellbeing induces problematic SMU, also may be plausible (Marino et al., 2018b). While some longitudinal studies provide evidence for a causal pathway whereby problematic SMU would negatively affect (mental) wellbeing (Boer, Stevens, et al., 2020; Van den Eijnden et al., 2018), other research suggests a reverse (Raudsepp & Kais, 2019) or bidirectional pathway (Li et al., 2018). Also, all measures were based on self-reports which may deviate from, for example, actual frequency of SMU (Orben & Przybylski, 2019a, 2019b). Further, our measure of intense SMU was a measure of active SMU (i.e., using social media to communicate), and not of passive SMU (i.e., scrolling through profiles). A different measure of intense SMU that includes passive use may have yielded different results, as research suggests that passive use mainly decreases wellbeing (Verduyn et al., 2015; Wenninger et al., 2014), while active usage may enhance wellbeing (Verduyn et al., 2017). Taking these limitations into account, longitudinal research on the direction of the association between (problematic) SMU and wellbeing,