Children's Sleep

Professor Russell Viner, President, Royal College of Paediatrics and Child Health co-authored a report, whose findings suggested that sleep is a more important factor than online activity in children’s mental health.
The researchers made the point that parents should worry less about the amount of time their children spend on social media during the day and instead make sure their offspring get enough sleep.
One approach that parents can take is to keep phones out of children’s bedrooms, adding that teenagers need up to 10 hours’ sleep a night.
On a similar note, but in a different context, Wendy M. Troxel, PhD, internationally recognized for her work on sleep and a senior behavioral and social scientist at the RAND Corporation* and an adjunct faculty member in psychiatry and psychology at the University of Pittsburgh, worries about sleep deprivation due to how early school starts, especially in the U.S.A..
(*The RAND Corporation is a nonprofit institution that helps improve policy and decision-making through research and analysis.
For seven decades, RAND has used rigorous, fact-based research and analysis to help individuals, families, and communities throughout the world be safer and more secure, healthier and more prosperous. Its research spans the issues that matter most, such as energy, education, health care, justice, the environment, international affairs, and national security.
As a nonpartisan organization, RAND is widely respected for operating independent of political and commercial pressures. Quality and objectivity are its two core values).

Dr Troxel writes:
Without sufficient sleep, teens can’t function at their best. Research consistently finds inadequate sleep in teens is associated with increased risk of mental and physical health problems, including depression, suicide and obesity. It also creates problems with their concentration, memory and ability to learn.
She is especially attuned to how incompatible adolescent biology is with having to go to school early in the morning. Indeed, it’s led to an epidemic of sleep deprivation among American teens. In one study she worked on, nearly 2,000 teens from Los Angeles were tracked for four years finding that only 26% were getting the recommended 8 to 10 hours of sleep per night.
So what does she do to ameliorate the problem?
“At least two weeks before the first day of school, I start adjusting my kids’ sleep schedule, shifting them toward waking up when they need to during the school year. Our bodies adjust more easily if we make shifts in smaller increments, so I have my kids start setting their alarms about 15 minutes earlier each day and shift their bedtimes earlier by about the same amount. Depending on when you get started and how much of a shift your child needs to make, you may have to shift by larger increments.”
In addition to health problems, sleep deprivation also has measurable negative effects on teens’ behavior. In a recent RAND study, our team found that teens who did not catch up on sleep on the weekends were twice as likely to engage in risky sexual behavior — such as having sex without a condom or using drugs or alcohol before or during sex — than those who slept in. Our work and other studies have further shown that sleep problems are linked with an increased likelihood of teens using marijuana or alcohol or engaging in other dangerous behaviors such as reckless driving.
Even knowing all I do about sleep needs and patterns, there’s only so much I can do, frankly, when school starts at 7:35 a.m. — as it does in my kids’ case. There is a wave of individual school districts across the county that are delaying school start times to address the epidemic of teen sleep loss. The evidence shows when schools start later, teens get more sleep. They’re also more likely to show up for school, be on time, be ready to learn, and are more likely to graduate.
So, parents like me do what we can. We ease the transition for our kids. We let them catch up on sleep on the weekends — within reason. And we encourage our school districts to start heeding the science on teen sleep.”

In terms of worries concerning screentime activity see this report.

The advice is: make sure your children get enough sleep.