Study leader Michelle Garrison of the University of Washington School of Public Health in Seattle said the study involved 565 families. Some parents were encouraged to let kids watch only programs such as "Sesame Street" and "Curious George." The rest were not.
"After one year, we really saw significant improvements in sleep of the group which kept kids away from violent programs that included things such as decreased night wakings and nightmares, having an easier time falling asleep at night, being less cranky in the morning and just less tired during the day," Garrison said in a statement.
The study was published in the journal Pediatrics.