Maartje Boer

CHAPTER 4 118 Figure 4.3 Associations Between Problematic SMU and Wellbeing Notes. SMU = social media use; B = unstandardized coefficient; M = mean. Left (A): dots denote average estimated associations between problematic SMU and the wellbeing outcomes, horizontal lines through the dots denote their 95% prediction interval. Right (B): diagonal lines represent the estimated associations of problematic SMU and the wellbeing outcomes by the country-level prevalence of problematic SMU. Cross-level interactions were reported when they improved model fit and when they were significant at p < 0.05. All estimates were derived frommultilevel regression models (Appendix, Table A4.1). * p < 0.05, ** p < 0.01, *** p < 0.001. Social Wellbeing In all countries, problematic users reported less family support than non- problematic users ( B = -0.619, p < 0.001; 95% PI = -0.826 to -0.396). The higher the country-level prevalence of problematic SMU, the weaker this association was ( B = 2.183, p = 0.026; Figure 4.3B). This cross-level interaction explained 25.0% of the country-variance in this association. The country-level prevalence of intense SMU did not explain any country-variance in this association. In all countries, problematic users reported lower levels of friend support than non-problematic users ( B = -0.343, p < 0.001; 95% PI = -0.516 to -0.144) . The higher the country-level prevalence of problematic SMU, the weaker this