Similarities and differences in the late-onset GM2 gangliosidoses: Tay-Sachs and Sandhoff diseases.

Screen-based digital devices, such as television, cell phones, computers, and tablets, have become deeply embedded in children’s lives in the past 2 decades. In the UK, 85% of children aged 3 to 5 years use screen-based devices to go online, increasing to 100% by 10 years of age, and 81% of children aged 10 to 12 years use social media and messaging apps despite a mandated age limit of 13 years. This widespread exposure has raised concerns among researchers, policymakers, and the media about potential detrimental effects on childhood and adolescent psychosocial development, although evidence remains inconsistent and much debated. Large reviews have reported mixed findings, reflecting small sample sizes, heterogeneous methods, and limited adjustment for key confounders, such as parent-child interaction. Screen type and duration may also affect age groups differently: young children appear more sensitive, possibly through reduced parent-child interaction and play, whereas evidence in adolescents has been less consistent, partly reflecting the dynamic biological and social changes of this developmental stage. Most studies are cross-sectional and provide only a snapshot at a single time point. Two longitudinal cohort studies from Ireland and New Zealand reported no major long-term detrimental effects of early screen use on psychosocial development, but neither study extended into the teenage years or evaluated parent-child relationships. Given the predominance of cross-sectional designs, limited evidence in adolescence, and inadequate adjustment for key family-level confounders, high-quality, longitudinal evidence is urgently needed to address whether and how screen use is associated with psychosocial development throughout childhood and adolescence and to inform policy. Using data from a large Scottish birth cohort study, we aimed to (1) examine cross-sectional associations between screen use and psychosocial development at the ages of 5, 10, and 15 years, with adjustment for parent-child relationships; (2) describe changes in screen use from the ages of 5 to 15 years; and (3) examine whether screen use at 5 years of age was associated with Strengths and Difficulties Questionnaire (SDQ) outcomes at 10 and 15 years of age. This secondary analysis of a cohort study obtained data from the Growing Up in Scotland (GUS) study and conducted analyses between April 2025 and March 2026. GUS study procedures included obtaining written and oral informed consent from main carers and children (once they reached approximately 8 years of age) for data access by researchers not directly involved in the GUS study. Therefore, no additional consent for this analysis was sought. Ethical approval and sponsorship for this study were granted by the University of Edinburgh Usher Masters Research Ethics Group. This study followed the Strengthening the Reporting of Observational Studies in Epidemiology () reporting guideline for cohort studies. GUS is a Scottish government–funded birth cohort administered by the Scottish Centre for Social Research (ScotCen). Infants aged 10 months living in Scotland in 2005 to 2006 were identified from child benefit records (>90% of Scottish children) and followed up at regular intervals with interviews, standardized questionnaires, cognitive tests, and physical measurements (eFigure 1 in ). An additional sample (n = 502) of adolescents was recruited in 2017 to redress the differential unavailability for follow-up of children from the most deprived areas. They were included in the cross-sectional analysis of screen use and SDQ at 15 years of age but excluded from the longitudinal analysis because data from earlier ages were not available for this subsample. The current study used data collected in 2009 to 2010, 2014 to 2015, and 2019 to 2020, corresponding to the ages of 5, 10, and 15 years. A flow diagram of the participant sample over time is shown in eFigure 2 in . These time frames are important in the context of this study because some of the currently most popular screen-based activities and apps among children and adolescents were launched later in the data collection period (eg, TikTok launched in the UK in August 2018).