The association between social media addiction and psychological well-being in adolescents with sequential mediation by physical activity and loneliness

Social media addiction is a phenomenon that may adversely affect adolescent mental health and is increasingly recognized as a public health concern by international authorities such as the World Health Organization. Understanding the potential mechanisms underlying the association between social media addiction and psychological well-being is important for informing effective intervention strategies. This study aimed to examine the sequential mediating role of physical activity and loneliness in the association between social media addiction and adolescents’ psychological well-being. This cross-sectional study included 290 high school students (mean age = 15.73; 59% female, 41% male) enrolled in high schools in Türkiye. Data were collected using the Bergen Social Media Addiction Scale, the International Physical Activity Questionnaire, the UCLA Loneliness Scale (Short Form), and the Psychological Well-Being Scale. Data were analyzed using SPSS. Normality assumptions were first examined, followed by descriptive statistics and Pearson correlation analyses to assess the relationships among the study variables. Subsequently, Hayes’ PROCESS Macro Model 6, a bootstrap-based sequential mediation analysis, was employed to examine the hypothesized indirect associations. Social media addiction was significantly and negatively associated with psychological well-being. The sequential mediation analysis indicated that social media addiction is associated with lower levels of physical activity, which in turn is associated with higher levels of loneliness, and that the proposed sequential indirect association with psychological well-being was statistically significant (indirect effect = -0.0259, 95% CI [-0.0488, -0.0072]). Conclusion The results indicate that physical activity and loneliness may represent an important sequential pathway in the association between social media addiction and adolescents’ psychological well-being. Accordingly, public health interventions targeting adolescent mental health may benefit from addressing social media use while also promoting physical activity as a potential component of strategies to support psychological well-being. © The Author(s) 2026.