Abstract
The proliferation of "fake news" has emerged as a global public health challenge. Evidence indicates that fake news spreads faster than verified information, undermines trust, and is associated with psychological distress. This study aimed to examine Vietnamese adolescents' and young adults' exposure to fake news on social networking sites (SNS), their coping strategies, and related mental health outcomes. An online cross-sectional study was carried out in three cities in Vietnam (Hanoi, Tuyen Quang, and Can Tho) from September to October 2021. The questionnaire used in this study comprised five components. Multivariate ordered logistic and Linear regression models were employed to determine factors related to experiences with fake news, its coping strategies as well as associated psychological outcomes. Among 1850 participants, the majority were students (92.9%), urban residents (91.5%), and females (57.0%). Overall, 68.8% reported at least occasional exposure to fake news on social networking sites. Nearly half tended to ignore fake news (47.1%), while fewer intervened to counter its spread (16.2%) or joined in sharing it (7.1%). Frequent exposure to fake news, heavy SNS usage, and problemtic SNS usage were associated with higher PHQ-9 and GAD-7 scores, and a greater likelihood of sharing fake news. Furthermore, higher problematic internet use predicted passive (ignore) or harmful coping (join in to share). Notably, participants with greater digital literacy reported more frequent exposure. The findings highlight fake news exposure on SNS as a predictor of mental well-being in young populations. Strengthening digital literacy education, promoting healthy online engagement, and expanding mental health support systems should be prioritised in rapidly digitalising settings such as Vietnam.