Trait emotion regulation predicts momentary self-esteem level and variability in adolescents' daily lives.

Level and variability are two key aspects of momentary self-esteem that are associated with mental health from early adolescence onwards, but little is known about their determinants. The current study examines how the trait-level use of four emotion regulation strategies-reappraisal, reflection, expressive suppression, social sharing-is associated with the level and variability of momentary self-esteem in the developmentally critical period of adolescence. Using mixed-effects location scale models, we analyzed experience sampling data from 408 adolescents (14-22 years, 81.62% girls) who reported their momentary self-esteem up to 35 times across one week. Two findings stand out: first, adolescents who tended to engage more in reappraisal, reflection, and social sharing to regulate their emotions experienced higher momentary self-esteem levels, whereas those who tended to engage more in expressive suppression experienced lower levels. Second, the tendency to use expressive suppression was consistently linked to more variability in momentary self-esteem. We discuss the contribution of emotion regulation strategies to levels of momentary self-esteem in adolescence and highlight the need for further research into the mechanisms underlying its variability.