Research on Adverse Physiological and Psychological Effects of Screen Time on Children and Adolescents

Research indicates that excessive screen time among children and adolescents has become a significant public health concern, with prolonged digital media use associated with a range of adverse physiological, psychological, and neurological outcomes (Lissak, 2018). As digital devices such as smartphones, tablets, computers, and gaming consoles become increasingly integrated into daily life, several factors influence the severity of these effects, including duration of use, type of content accessed, nighttime use, and dependency on multiple devices.

Excessive screen exposure has been associated with numerous physical health consequences, with poor sleep quality identified as a key mediating factor in many health outcomes. Sleep disruption resulting from screen use, particularly before bedtime, has been linked to increased sympathetic nervous system activation, cortisol dysregulation, obesity, insulin resistance, elevated blood pressure, reduced high-density lipoprotein (HDL) cholesterol, and an increased long-term risk of cardiovascular disease. Additional physical consequences include digital eye strain, impaired visual development, reduced physical activity, and lower bone density due to prolonged sedentary behaviour.

Psychological effects are similarly concerning, with excessive screen use associated with both internalising and externalising behavioural difficulties. Internalising symptoms may include anxiety, depression, emotional withdrawal, and reduced self-esteem, while externalising symptoms may manifest as irritability, aggression, impulsivity, and behavioural dysregulation. Poor sleep quality appears to significantly contribute to these emotional and behavioural difficulties, with excessive nighttime device use and mobile phone dependency also associated with depressive symptoms and suicidal ideation among adolescents. Attention difficulties and ADHD-like behaviours have also been linked to excessive screen exposure, particularly when children engage with fast-paced or violent digital content that overstimulates dopamine reward pathways and reduces attentional control over time.

From a social and neuropsychological perspective, problematic or addictive screen use may interfere with healthy emotional development and interpersonal functioning. Excessive digital engagement may reduce opportunities for face-to-face social interaction, weaken adaptive coping skills, and foster emotional dependency on digital stimulation for comfort or self-regulation. Exposure to violent media content, especially from an early age, has also been associated with increased antisocial behaviour and reduced prosocial responses. Neurobiological evidence further suggests that problematic digital media use may activate reward systems in a manner similar to behavioural addiction, producing craving-like responses and compulsive engagement patterns. Structural and functional brain changes have also been observed in areas associated with emotional regulation, impulse control, and executive functioning. Collectively, these findings highlight the potential for excessive screen time to significantly impact children’s physical health, emotional wellbeing, social functioning and neurodevelopment.