<p>Examining only screen time and addictive use may overlook critical aspects of social media use. Therefore, this study aimed to explore social media screen time, addictive use, motives, and content—both interrelations and how these variables are associated with psychosocial problems. We also examined sex differences. High school and university students (<i>n</i> = 1820) completed a digital survey. Interrelations between the social media use variables were mostly significant, but modest, and the variables explained as much as 33–40% of the variance in psychosocial outcomes (i.e., psychosomatic problems, low self-esteem, and social problems). Addictive use in terms of negative consequences was related to all three outcomes. In addition, the motive Escape and Appearance-based content were strongly related to both psychosomatic problems and low self-esteem, whereas the motive Social Compensation and Negative content were strongly related to social problems. Females scored higher on most social media use variables, including a higher prevalence of social media disorder. Sex moderated some associations, but interaction effects were small. Associations were primarily linear. Conclusively, social media content and motives explain a large amount of the variance in psychosocial outcomes, emphasizing the importance of moving beyond screen time. Future research should further investigate these aspects to develop more targeted interventions aimed at reducing social media’s negative mental health impact.</p>