In 2017, in order to contribute to reflection on so-called "substance-free" addictions among adolescents, the French Monitoring Centre for Drugs and Drug Addiction (OFDT) integrated a new module on the use of various electronic devices with screens into its Survey on Health and Use on National Defence and Citizenship Day (ESCAPAD). This memo reports the main results on the issue of the amount of time 17-year-olds spend on screens, distinguishing between the different types: televisions, game consoles, computers, tablets and mobile phones. Furthermore, in an exploratory and transversal approach to the various different kinds of screens, the memo focuses on the relationship between adolescents and social networks in terms of excessive use, as well as their ability to disconnect from their mobile phones.