Digital Psychological Immunity: Synergistic Suppression of Multidimensional Health Literacy on Adolescent Social Media Addiction and Depression-Anxiety-Stress (Preprint)

BACKGROUND Amid China’s escalating adolescent mental health crisis, exacerbated by digital environments, this study examines how a tripartite health literacy system—comprising eHealth literacy, mental health literacy, and mental eHealth literacy—synergistically mitigates social media addiction and depression-anxiety-stress. OBJECTIVE Given the compatibility of these theoretical propositions, this study aims to investigate the multifaceted effects and underlying mechanisms of multidimensional health literacy—encompassing Mental Health Literacy, eHealth Literacy, and Mental eHealth Literacy —on adolescent Social Media Addiction and psychological distress (Depression-Anxiety-Stress). The findings will offer a theoretical foundation for developing effective mental health interventions and optimizing adolescent mental health management strategies. METHODS A total of 855 high school students (M = 16.38, SD = 0.86) from five provinces in China were recruited using stratified cluster sampling. Standardized scales were employed to assess eHealth literacy, mental health literacy, mental eHealth literacy, social media addiction, and depression-anxiety-stress. Structural equation modeling (SEM) and Hayes' PROCESS macro were used to analyze the data, testing direct, mediating, and moderating effects of the health literacy dimensions. RESULTS The results revealed that both eHealth literacy and mental health literacy directly reduced social media addiction. However, only mental health literacy significantly alleviated depression-anxiety-stress. Mental eHealth literacy was identified as a significant mediator in both pathways. Furthermore, mental health literacy was found to positively moderate the effect of eHealth literacy, creating dual moderated mediation pathways that influenced both addiction and psychological distress. CONCLUSIONS This study presents the "Digital Psychological Immunity" framework, elucidating the synergistic role of multidimensional health literacy in mitigating social media addiction and psychological distress. The findings provide theoretical support for national adolescent mental health initiatives, emphasizing the need to concurrently enhance both mental health literacy and digital literacy in addressing the challenges of the digital age. CLINICALTRIAL This study was approved by the Academic Ethics Committee of Capital University of Physical Education and Sports (Approval No. 2025A0105). All participants provided informed consent prior to participation.