Quantity and Quality of Digital Life: A Mediation and Moderation Analysis of Psychological Outcomes through Problematic Internet Use

Background: Research on internet use and mental health has often focused narrowly on screen time, overlooking the differential effects of how much and how the internet is used. Emerging evidence suggests that the quality of online engagement (types and purposes of use) and its interaction with problematic internet use (PIU) may provide a more nuanced explanation of psychological outcomes. Hence, this study examined how the quantity and quality of internet use relate to well-being, depression, anxiety, and stress, with various mediators and moderators. Methods: A cross-sectional survey was conducted among 493 college students in the two north-eastern states of India. Measures included the Adult Internet Usage Questionnaire, the Internet Addiction Test, the Mental Health Continuum, and the DASS-21. Data were analyzed using hierarchical regression and PROCESS Macro (v4.1) to test mediation and moderation models. Results: Quantity and quality of internet use did not uniformly predict psychological outcomes. PIU consistently mediated the relationship between both dimensions of internet use and well-being, depression, anxiety, and stress. While quality of use was directly associated with greater well-being, its effect on negative mental health outcomes was limited. Moderation analyses revealed that gender and quantity of use further shaped specific pathways, particularly in health-related and social network use. Conclusion: The findings challenge the adequacy of screen-time metrics and underscore PIU as the central mechanism linking internet use to mental health. Interventions should focus on fostering purposeful engagement while preventing maladaptive usage patterns.