Effects of Excessive Screen Time on Neurodevelopment, Learning, Memory, Mental Health, and Neurodegeneration: a Scoping Review

Abstract

Evidence suggests that chronic sensory stimulation via excessive exposure to screen time may affect brain development in negative ways. Excessive smartphone use may increase the risk of cognitive, behavioral, and emotional disorders in adolescents and young adults that also has the potential to increase the risk of early onset dementia in late adulthood. This scoping review assessed theoretical and empirical evidence for the relationships between excessive screen time and (i) neurodevelopment, (ii) learning and memory, (iii) mental health, (iv) substance use disorders, and (v) neurodegeneration. Using Halas et al.’s (BMJ Open, 5(1), 1–6; 2015) five-stage scoping review methodology, we systematically identified articles meeting the following inclusion criteria: published in English between January 1999–July 2019; human or animal subjects; primary and secondary sources including original research, systematic reviews, meta-analyses, scoping reviews, and narrative reviews. Primary search terms focused on “smartphone,” “mental health,” “substance use,” “neurodevelopment,” and “neurodegeneration”; secondary search terms focused on “social media,” “anxiety,” “cannabis,” and “dementia”. We analyzed 44 articles across 16 countries in this review. Each article corresponded to one of four research questions investigating screen time and mental health (n = 13), mental health and substance use (n = 8), chronic stress and development (n = 14), and chronic stress and neurodegeneration (n = 9). Overall increased screen time is associated with negative outcomes such as lowered self-esteem, increased incidence and severity of mental health issues and addictions, slowed learning and acquisition, and an increased risk of premature cognitive decline. Future directions to better inform public policy should expand research methodologies and explore the prolonged effects of excessive screen time on cognition and mental health in diverse populations and contexts.