O019 Mobile phone use at night, cyber-bullying, sleep, and mental wellbeing in young people aged 7 to 19 years

Introduction Children commonly have access to mobile devices that allow them to send and receive texts at night when they should be sleeping. This may contribute to an increase in cyber-bullying and sleep problems, with negative effects on mental wellbeing. Methods Young children (7-11y, n = 22,597), early adolescents (12-14y, n = 19,470) and late adolescents (15-19y, n = 14,156) completed a survey examining mental wellbeing and the frequency of obtaining 8h sleep, texting at night and cyber-bullying.. Generalised structural equation modelling was used to investigate the effects of texting at night on mental wellbeing, directly, and indirectly via effects on sleep. Cyber-bullying was also specified as a moderator of the effect of texting at night on sleep. Results Text messaging at night in the last week was reported by 51% and cyber-bullied in the last school term by 15% of children. For all children, obtaining at least 8h of sleep increased the odds of better mental wellbeing, Conversely, texting messaging and cyber-bullied reduced the odds of obtaining 8h sleep in both male and female young children and female early and late adolescents. In all cohorts except late adolescent males, obtaining less than 8h sleep and cyber-bullied accounted for a large proportion of the effects of text messaging on mental wellbeing. Conclusion Mobile phone use at night impairs sleep which contributes to poor mental wellbeing. The effect on sleep is exacerbated by cyber-bullying. Strategies to discourage small screen use at night, promote adequate sleep and reduce cyber-bullying are needed.