Oxford University researchers analyzed data from studies tracking the screen time usage of 17,000 teenagers from the UK, USA, and Ireland. Screen time is defined as time in front of a computer, game console, or mobile device while playing games, texting, emailing, using social networks, or streaming movies and TV shows. The researchers also focused on measuring if screen time right before bed had a negative effect, which led the researchers to conclude that there were no substantial issues with screen time before bed.
Source: https://www.bleepingcomputer.com/news/technology/study-shows-screen-time-before-bed-is-not-bad-for-teenagers/