Neural, psychological, and transcriptomic predictors of short video addiction: A multi-site longitudinal study of fear of missing out and negative affect.

Short video addiction symptoms (SVAS) have become increasingly prevalent, yet their longitudinal neurobiological basis remains unclear. In a multi-site longitudinal study (n = 280), we examined whether baseline brain features and dispositional traits-negative affect (NA) and fear of missing out (FoMO)-predict future SVAS. Participants completed self-report measures and MRI scans at baseline, with follow-up assessments conducted after 5 months to 5 years. Behaviorally, both baseline and follow-up NA and FoMO significantly predicted SVAS. Structurally, baseline gray matter volume (GMV) in the frontal-parietal network (FPN), default mode network (DMN), and hippocampal morphological patterns predicted follow-up SVAS severity. Functionally, baseline regional homogeneity (ReHo) in the FPN, DMN, ventral attention network (VAN), and sensorimotor network (SMN) also predicted SVAS. Parallel multiple mediation analyses revealed a dissociable neural architecture: hippocampal morphological patterns predicted SVAS via the unique indirect effect of follow-up FoMO, whereas DMN functional profiles (e.g., ReHo) predicted SVAS via follow-up NA. Notably, the VAN served as an integrative hub, exerting its influence via the unique indirect effects of both follow-up NA and FoMO. Transcriptomic analyses linked SVAS-related ReHo to two gene sets, namely positively correlated (SVAS-ReHo⁺) and negatively correlated (SVAS-ReHo⁻) genes. SVAS-ReHo⁺ genes were enriched in RNA processing and vascular signaling and expressed in endothelial cells; SVAS-ReHo⁻ genes were enriched in synaptic transmission and expressed in excitatory and inhibitory neurons. Spatial-temporal patterns showed SVAS-ReHo⁺ genes were expressed in subcortical regions across adolescence, whereas SVAS-ReHo⁻ genes were prominent in cortical-limbic areas during postnatal development. Functional decoding linked SVAS-ReHo⁺ genes to sensorimotor function and metabolism, and SVAS-ReHo⁻ genes to emotion and psychiatric risk. Together, these findings highlight dissociable structural, functional, and molecular pathways through which FoMO and NA contribute to short video addiction development.