Affective reactivity to upward social comparisons rather than social media use predicts increases in early adolescents' depressive symptoms.

Youths differ substantially in how they emotionally respond to daily experiences. Repeated episodes of heightened negative affect in daily life may accumulate over time and increase vulnerability for developing depressive disorders. This study examined whether individual differences in negative affective reactivity to daily social experiences (i.e., social media use and upward social comparisons) predict changes in depressive symptoms over two weeks. Using a 14-day diary design with 200 early adolescents (103 female; ages 10-14), we assessed daily social media use, daily upward social comparisons, daily negative affect, and depressive symptoms at pre- and posttest. We employed multilevel structural equation modeling, estimating the within-person coupling between daily social media use (Model 1) or upward social comparisons (Model 2) and daily negative affect and tested whether between-person differences in the strength of this coupling predicted average negative affect and depressive symptom change. Findings revealed that a stronger within-person coupling between upward social comparisons and negative affect, but not between social media use and negative affect, was associated with an increase in depressive symptoms via elevated negative affect across the study. These results highlight the importance of capturing dynamic affective responses to daily social comparison processes when assessing psychological risk in early adolescence.