CNN: Students who reported high use of cellphones also reported poor sleep quality, finds a study published in Frontiers in Psychiatry.

“This is a cross-sectional study, and as such cannot lead to any firm conclusions about phone usage as the cause of reduced sleep quality,” said Bob Patton, a lecturer in clinical psychology at the University of Surrey, via email.

“It does, however, provide some compelling evidence that the nature of smart phone usage and its related consequences are important considerations in addressing the emerging phenomenon of ‘smartphone addiction,'” said Patton, who is lead for the Drugs, Alcohol & Addictive Behaviours Research Group at the university.