From Quest for Significance to Social Media Addiction: The Mediating Role of Boredom and the Moderating Role of Age in a Spanish Sample

(1) Background: Social media addiction (SMA) is conceptualized as a behavioral addiction linked to emotional dysregulation. This study investigates whether multidimensional state boredom mediates the relationship between the quest for significance and SMA, exploring the moderating role of age cohorts. (2) Methods: A cross-sectional study was conducted with 316 Spanish participants (aged 18–68) divided into Generation Z, Millennials, and Generation X. Standardized measures (BSMAS, SQS, MSBS) were analyzed using a multiple moderated mediation model (PROCESS Model 14), controlling for gender. (3) Results: Boredom dimensions correlated positively with both quest for significance and SMA. The final model explained 53.5% of SMA variance. High-arousal boredom and inattention were positively associated with SMA, while low-arousal boredom showed a negative association. Notably, the quest for significance was indirectly associated with SMA through high-arousal boredom exclusively among Generation Z, with no significant indirect effects found in older cohorts. (4) Conclusions: The findings highlight high-arousal boredom as a key link between existential motives and SMA, particularly in younger individuals. These results underscore the importance of age-specific emotional and motivational processes in designing prevention and intervention strategies for problematic social media use.