Nearly 10,000 teenagers between the ages of 16 and 19 in Norway participated in the study.
Scientists have known for a while that light from laptops and smartphone screens disrupts our biological clocks.
But light is not the only problem. The emotional stimulation of chatting to friends could also be playing a part.
It sounds simple, but the best way to combat screen-based sleep deprivation is to keep your screens out of the bedroom entirely, says Hysing.