The lighted screens of electronic devices attract kids’ eyes in school and at home—and they could be harming sleep patterns, reports SCTimes.

Scientific research and interviews with psychologists, professors and others present a complex picture with one clear piece of advice: Kids should avoid screens at bedtime.

Doctor Jon Dennis said screens affecting sleep is “a significant problem.”

“There should not be a TV in a child’s bedroom, period,” he said.

The St. Cloud pediatric and adolescent physician also cautioned parents about content on tablets, smartphones, computers and TVs. He said elements in some supposed child-friendly films can be traumatizing.