Maartje Boer

SMU AND MENTAL HEALTH 177 6 Discussion The present study investigated bidirectional associations between SMU and mental health using longitudinal data collected among adolescents. In doing so, we distinguished between SMU intensity and addiction-like SMU problems. We also examined whether the proposed bidirectional associations were mediated by upward social comparisons, cybervictimization, decreased subjective school achievements, and less face-to-face contact. Findings showed that adolescents whose SMU problems increased reported increased depressive symptoms and decreased life satisfaction one year later. Also, SMU problems predicted increases in upward social comparisons and cybervictimization over time. Yet this, in turn, did not predict increases in depressive symptoms or decreases in life satisfaction over time, suggesting that upward social comparisons and cybervictimization did not mediate the observed effect of SMU problems on mental health. Reversely, increased depressive symptoms or decreased life satisfaction did not predict increased SMU problems one year later, neither directly nor indirectly through any of themediators. We did not observe any direct or indirect associations between SMU intensity andmental health over time: Adolescents whose SMU intensity increased did not report increased depressive symptoms or decreased life satisfaction one year later, and neither vice versa. Scholars have raised concerns about the adverse effects of SMU among adolescents (Primack & Escobar-Viera, 2017; Underwood & Ehrenreich, 2017). The present study suggests that particularly adolescents who show addiction-like SMU problems, but not adolescents who solely show high SMU intensity, are at risk for decreases in mental health. More specifically, being unable to control SMU impulses, constantly thinking about SMU, feeling bad when SMU is restricted, or attaching vital importance to SMU seem to evoke detrimental consequences to adolescents’ mental health, rather than using social media a lot. Thus, adverse effects of SMU may depend on the extent to which adolescents have agency over their SMU, and not on their frequency of SMU. To that end, adolescents who engage in high SMU intensity without any SMU problems may be well able to regulate their SMU; their SMU may not necessarily interfere with life domains relevant to their mental health. After all, nowadays, high SMU intensity has become an integral part of adolescents’ daily lives, and most adolescents use social media intensively to maintain