Background Children and teenagers are spending increasing amounts of time on screen based media; in contrast, total sleep duration has been declining in the last two decades. Researchers around the world continue to examine the association between screen time and sleep, with the last updated systematic review occurred in 2015.

Objectives Given the extensive use of screen-based media and the high prevalence of poor sleep amongst children and teenagers, our aim was to provide an update to the previous systematic literature reviews on the effects of time spent using screens on various sleep outcomes, adopting similar criteria for inclusion.

Methods A systematic search of peer-reviewed articles was conducted using OVID MEDLINE and EMBASE. The search parameters included papers up to March 2019, with no initial cut-off date.

We included all studies that used the following inclusion criteria:

1. Cohort of children or adolescents between the age of 5 and 17;

2. Examined the associations between any type of screen time and sleep outcomes, including sleep timing, sleep onset latency, sleep duration, sleep quality, daytime lethargy or sleepiness or any other reported outcomes related to sleep;

3. Published in the English language.

Results 99 studies were reviewed: 80% were cross-sectional studies, 16% were prospective studies and 3% were clinical trials. Studies included children and adolescents from countries around the world. 87% of the studies showed at least one adverse sleep outcome with screen use. 43 out of 56 (77%) studies reported significant negative impacts on sleep outcomes with television (TV) watching; Five studies showed that the mere presence of a television set in the room itself was associated with shorter sleep duration. 49 out of 53 studies reported negative effects on sleep with the use of interactive media; Amongst all technology types, social networking sites or video games at bedtime on weekdays appeared to have the greatest negative impact on sleep duration, after adjustment for a range of potential confounders. 90% of the studies related mobile device exposure to negative sleep outcomes; Sleep disturbances or insomnia-related symptoms were measured in 13 studies, with 11 reporting significant association with the use of mobile devices. Articles that either combined multiple screens into one measure or did not specify the screen type when examining its effect on sleep outcomes were categorised into unspecified screen use; 25 out of 27 studies (93%) found an adverse correlation with at least one sleep outcome with exposure to unspecified screens. Interestingly, parental control had a moderating effect on the relationship between bedtime and screen exposure.

Conclusions Current evidence suggests that an increased amount of screen exposure leads to adverse sleep outcome in children and adolescents. Unspecified screen use (93%), interactive media exposure (92%) and mobile devices use (90%) were consistently related to poor sleep outcomes. Future research is necessary to quantify a safe amount of screen exposure and determine if there is a causality link between screen time and sleep in children and adolescents.