Many studies have shown that the use of electronic media is related to sleep disturbance, but few have examined the impact of smartphones. The objective of this study was to assess longitudinally whether acquiring a smartphone had an effect on adolescents' sleeping duration. The study included 591 adolescents observed at baseline (T0, Spring 2012; mean age 14.3 years, 288 females) and 2 years later (T1). They were divided into owners (those owning a smartphone at T0 and T1; N = 383), new owners (those owning a smartphone at T1 but not at T0; N = 153), and non-owners (those not owning a smartphone at any time-point; N = 55). Groups were compared on sleep duration, sleep problems, and sociodemographic variables. Overall, all three groups decreased their sleeping time between T0 and T1. At T0, owners of a smartphone were found to sleep significantly less than non-owners and new-owners, especially on school days, and to report significantly more sleeping problems. At T1, new-owners and owners showed no differences on sleep duration or sleeping problems.
Conclusion: The results emphasize that owning a smartphone tends to entail sleep disturbance. Therefore, adolescents and parents should be informed about the potential consequences of smartphone use on sleep and health. What is Known: • The use of electronic media plays an important role in the life of adolescents. • Smartphone use is increasing among young people and allows them to be connected almost anytime anywhere. What is New : • Adolescents owning a smartphone sleep less hours on school days than their peers. • Smartphones seem to have an important impact on youths' sleep duration.
Keywords: Adolescence; Electronic media use; Longitudinal study; Sleep duration; Sleeping problems; Smartphone.