This review synthesises longitudinal and experimental evidence on social media use and well-being or mental health among adolescents and emerging adults, identifying 55 studies from 4,188 records through a PRISMA-based process (41 longitudinal and 14 experimental studies). Overall, the evidence does not support a single uniform association between social media use and poorer mental health across all young people: findings based on time- or frequency-based measures are mixed, often small, and sensitive to modelling choices, while reverse or bidirectional pathways remain plausible in some contexts. More consistent associations are found for problematic or dysregulated use, negative consequences, and harmful online experiences, although these measures also require cautious interpretation where they overlap conceptually with distress or impairment. Experimental evidence is informative for short-run, mechanism-linked outcomes, particularly appearance-related self-evaluative outcomes; evidence for FoMO is more conditional, and broader symptom changes are less consistent across studies and intervention designs. For policy, approaches focused only on reducing time online are likely to be imprecise unless they also consider dysregulated engagement, harmful online experiences, and specific risk pathways such as social comparison, appearance pressures and sleep disruption.

CABEZA MARTINEZ Begona;  CORTESI Alice;  VLACHOS Stavros; 

2026-05-18

Publications Office of the European Union

JRC146547

978-92-68-39415-1 (online),   

1831-9424 (online),   

EUR 40702,    OP KJ-01-26-178-EN-N (online),   

https://publications.jrc.ec.europa.eu/repository/handle/JRC146547,   

10.2760/3963302 (online),