The long-run effects of peers on mental health

This paper studies how peers in school affect students' mental health. Guided by a theoretical framework, we find that increasing students' relative ranks in their cohorts by one standard deviation improves their mental health by 6% of a standard deviation conditional on own ability. These effects are more pronounced for low-ability students, persistent for at least 14 years, and carry over to economic long-run outcomes. Moreover, we document a strong asymmetry: Students who receive negative rather than positive shocks react more strongly. Our findings therefore provide evidence on how the school environment can have long-lasting consequences for the well-being of individuals.