Investigating the cross-sectional and longitudinal relationship of X and LINE use with online relationship and life satisfaction: A 4-Year cohort study among Japanese adults

The rise of social media has sparked extensive research on its relationship with well-being, yet drawing definitive conclusions remains challenging due to the multifaceted nature and diversification of these platforms. To gain a clearer understanding of this relationship, it is essential to explore how various social media platforms both cross-sectionally and longitudinally relate to well-being as well as to explore direct and indirect relationships mediated by other factors. Such investigation is lacking especially in Non-Western context. To address this gap, the author examined the cross-sectional and longitudinal relationships of X (formerly Twitter) and LINE use with life satisfaction—a key indicator of well-being—both directly and indirectly through the quality of online relationships, within a 4-year cohort of 1,674 Japanese adults. Multivariate latent growth curve modeling revealed a mixed relationship between X use and life satisfaction. Direct relationships with life satisfaction were negative, both cross-sectionally and longitudinally. In contrast, an indirect relationship—mediated by online relationships—was positive both cross-sectionally and longitudinally. In contrast, LINE use consistently showed positive relationships with life satisfaction, with both direct and indirect positive cross-sectional associations through online relationships. These findings underscore the growing diversity of social media platforms and the need to recognize that the relationship between social media use and life satisfaction varies depending on the platform in both Western and non-Western contexts. To support well-being, public education and digital literacy efforts should address the risks of excessive use of open-network platforms like X, while avoiding overgeneralizations to closed-network platforms like LINE, which may enhance well-being through supportive relationships.