The relationship between trait mindfulness and problematic smartphone use: the serial mediation role of difficulties with emotion regulation and fear of missing out.

Problematic smartphone use (PSU) has emerged as a widespread behavioural concern, particularly among university students. The present study employed a preregistered design to ensure analytic transparency and confirmatory hypothesis testing, examining a serial mediation model under which difficulties with emotion regulation and fear of missing out (FOMO) explain the association between trait mindfulness and PSU in a sample of 406 Spanish university students. Participants completed validated self-report measures of trait mindfulness, emotion-regulation difficulties, FOMO and PSU. Data were analysed using correlation analyses and serial mediation modelling with bootstrapping procedures. The results reveal a negative association between trait mindfulness and PSU, supporting its role as a protective factor. FOMO emerged as a significant mediator in this relationship, whereas difficulties with emotion regulation did not have a significant direct mediating effect. However, a significant serial mediation pathway was identified: Higher levels of trait mindfulness were associated with fewer emotion-regulation difficulties, which, in turn, predicted lower FOMO, ultimately giving way to reduced PSU. This study contributes to a more integrative understanding of PSU by identifying key mediating mechanisms and supporting the development of interventions targeting mindfulness, emotion regulation, and FOMO in university populations.