Digital Habits, Attention Preservation, and Screen-Time Evidence for Vietnamese Adolescents 14–19: Empirical State, Mechanism, and Operational Practices Distinct from Popularised

Any guidance series for Vietnamese adolescents 14– 19 that addresses sleep, burnout, and academic performance must address digital habits, because digital exposure is the proximate channel through which sleep displacement, attention fragmentation, and social-comparison stress most frequently land in this cohort. This paper compiles the empirical evidence on screen time, social media, smartphone use, gaming, and attention regulation, with explicit treatment of the contested-evidence state and disaggregated confidence registers. Three questions are addressed. (a) What does the empirical screen-time / socialmedia literature say about adolescent academic performance, mental health, and attention regulation, disaggregated honestly across the 2018–2026 controversy? The Twenge 2017 iGen and 2023 update plus Haidt 2024 The Anxious Generation strongeffect case has substantial replication and effect-size pushback (Orben–Przybylski 2019 Nature Human Behaviour specificationcurve analysis, Vuorre–Przybylski 2024 cross-cultural critique, Odgers 2018, Ferguson 2017); the Braghieri–Levy–Makarin 2022 AJER Facebook quasi-experimental supplies a rare causal lens with college-age generalisability concerns. The operational implication: strong causal screen-time-to-depression claims are contested, while channel mechanisms (notification interruption, sleep displacement, multitasking cost) are high-confidence. (b) What are the Vietnamese-context patterns? Mobile-first internet, dominant gaming titles (Liên Quân Mobile, PUBG Mobile, Free Fire), TikTok / Facebook / Zalo platform stack, livestream and short-video consumption, online-tutor consumption, and examcycle doomscrolling are documented from VnExpress / Tuổi Trẻ reportage 2023–2026. (c) What is the operational practice set? The substantive artefact is the Practice × EvidenceConfidence × Deployability table (§5.5), ranking 11 practices. Notification configuration, phone-and-bed separation, and singletasking blocks carry the strongest mechanistic evidence and best deployability; consumption-discipline (algorithm awareness, doomscrolling self-checks, social-comparison limits) is secondtier; gaming-and-livestream regulation is third-tier with bounded evidence. The set is non-moralistic — operational discipline only — and integrates with i5.3 sleep substrate and i5.2 burnoutprevention. Strong claims are presented as contested; highconfidence claims (notification disrupts focused work; phone-inbed displaces sleep; media multitasking has measurable cognitive cost) are developed carefully. The deliverable is operational