Most studies about screen time versus sleep time involve children and teens. Here’s one that looks at effects in adults. The online journal JAMA Network Open confirms sleep disruptions from electronic screen time in the hour before bedtime resulted in later bedtime and nearly an hour less sleep per week. Specifically, participants who reported daily screen use prior to bed had one-third higher association with poor sleep. That’s about twice the percentage who reported no screen use. The study showed people who were morning chronotypes—that is, were at their best performance earlier in the day—were less affected by screen exposure than evening chronotypes.