Problematic social media use (PSMU) is characterized by compulsive and out of control use of social media platforms. PSMU is increasingly recognized as a significant issue with potential negative impacts on mental well-being and vulnerability to online harm. However, the current understanding of why certain individuals develop problematic use while others do not is limited, highlighting the need for further research to explore the social and behavioral factors that contribute to this issue.

This dissertation draws on a broad range of social scientific theories, such as theories on social belonging, the social identity theory, theories on loneliness and digital technologies, and crime opportunity theories, and it provides a comprehensive outlook on the development and outcomes of PSMU. The central aim of the research was to understand how the social needs and desire for connection—specifically, feelings of loneliness and identity-driven social media use—drive individuals toward PSMU.

The dissertation presents four research articles, each offering a unique perspective on PSMU. The articles were based on two longitudinal datasets collected in Finland in 2017–2020 and 2021–2023. The data were analyzed using statistical methods for panel data analysis. The results highlight that PSMU negatively impacts subjective wellbeing, with loneliness playing a mediating role. In addition, problematic use increases the risk of cybervictimization, and routinized online activities mediate this effect. Furthermore, identity-driven social media use significantly contributes to the development of PSMU, and individuals motivated by self-expression and social validation are more prone to problematic use. Finally, a reciprocal and dynamic relationship between PSMU and loneliness was identified.

This dissertation argues that PSMU is driven by unmet social needs, particularly the desire for social connection and identity validation. The research contributes to the growing body of literature on unhealthy online behaviors by identifying the drivers and consequences of excessive social media use. The results may help to recognize those who are at risk of becoming problematic users and to understand how problematic use can undermine their quality of life.