{"p"=>"Short-form videos (SFVs) deliver digital content in a way that sets them apart from other media. Concerns have arisen that such user interfaces may diminish attention, memory and emotional wellbeing in young people, yet evidence has not previously been synthesised for this demographic and in isolation from other media types. To assess the association between exposure to SFV-interfaces and neurocognitive outcomes in individuals aged $$\\varvec{\\le 25}$$ years, and to appraise the certainty of this evidence. Following PRISMA and Cochrane guidelines, four databases (PubMed, PsycINFO, WoS, Cochrane Reviews) were searched (2015–2025). Of 1,498 records, 42 studies (N = 46,912; mean age = 16.8) met the PICOS criteria. Most were cross-sectional (88%), with two longitudinal, one EEG, and one MRI study. Risk of bias and quality were evaluated using GRADE. Heavy, unstructured SFV use (typically $$\\varvec{\\ge 4}$$ h/day) was consistently associated with: small-to-moderate increases in inattention ($$\\varvec{\\beta \\approx 0.30}$$) and impulsivity ($$\\varvec{\\beta \\approx 0.25}$$); moderate reductions in working-memory span ($$\\varvec{\\beta \\approx -0.75}$$) and self-regulation ($$\\varvec{\\beta \\approx -0.45}$$); moderate elevations in anxiety ($$\\varvec{\\beta \\approx 0.35}$$), depression ($$\\varvec{\\beta \\approx 0.48}$$) and stress ($$\\varvec{\\beta \\approx 0.32}$$); and a moderate-to-large surge in addiction symptoms ($$\\varvec{\\beta \\approx 0.60}$$). Two cross-sectional imaging studies also reported associations between heavier short-video use and neurobiological measures. These included grey-matter volume differences in the orbitofrontal cortex and cerebellum, altered resting-state signal synchrony, and reduced P300 amplitudes. Protective factors included supportive environments, digital routines, and digital literacy. Consistent, albeit preliminary, evidence links excessive SFV watching to cognitive and emotional challenges in youth. Longitudinal and experimental studies are urgently needed, alongside trials of modifiable levers to reduce addiction-like use and related harms."}