A mediation analysis of the influence of sleep on the relationship between smartphone screen time and youth mental health

Research using subjective measures suggests that young people spend large amounts of their leisure time using digital media, which may affect their mental health. Of particular concern is that smartphone screen-time may replace health-promoting activities such as sleep and thereby contribute to mental health problems. Considering that previous studies primarily relied on subjective reports of screen-time and its effects on youth mental health, the objective of the current research was to examine whether screen-time objectively measured via mobile sensing was associated with internalizing (e.g., anxiety, depression) and externalizing (e.g., impulsivity, aggression) symptoms and whether this association was mediated by reduced sleep duration. 407 Canadian youths aged 15–25 completed questionnaires about their mental health symptoms and used a mobile sensing app to measure screen-time and sleep for at least 14 days. The association between screen-time and mental health symptoms and the mediation of sleep duration were tested by fitting structural equation models. Results suggested that objectively measured smartphone screen-time was indirectly associated with externalizing symptoms through reduced sleep duration, but showed no significant association with internalizing symptoms. These findings complement previous research that used subjective measures and highlight the need to provide support and resources to youth to promote healthy screen use and healthy sleep habits.