PARENTS will be relieved that schools are back in session. But even before the new term got going there was controversy in the media over how much screen time children should be allowed to have.

Many children may have received a digital device for Christmas and will, no doubt, have spent many hours downloading apps, visiting social media sites and playing games. Parents, I hope, will have rules set in place about when such devices can be used and for how long.

Good parents monitor the sites and activities their children access and do online.

Technology use in classrooms is also subject to major arguments in real life and, paradoxically, online. Some teachers argue technology in the classroom is good, others say that it should be very limited or banned.

A number of schools make a virtue out of “banning” mobile phones, others will incorporate the use of mobile phones in lessons for appropriate activities such as using one as a calculator or, in science, recording experiment outcomes.

The fact is, the technology genie is out of the bottle and we can’t put it back and push in a cork to keep it there.

The internet exists, it isn’t going away. Social media is a worldwide phenomenon that also will not stop simply because we don’t like it. Smart phones are not going to go away. But does allowing children to use screens cause any physical or mental harm?

In 1988 research was published that described how children’s and young people’s increasing “screen time” (that is, watching television) was leading to the displacement of other, more healthy activities.

This so-called displacement theory concluded that children viewing TV for more than four hours per day resulted in “negative effects”. This research guided a lot of policy with respect to advice to parents on monitoring and limiting children’s screen time.

The research suggested that the harmful effects of technology were directly proportional to the time spent engaging with that technology.

Since 1988 the options and opportunities for young people to access devices with screens has increased due to the advent of smart phones, tablets and laptop computers.

Digital screens are now a fixed feature of day to day living. They can appear in many devices that, in 1988, would not have been envisaged, for example touch screen satellite navigation, ticket purchasing machines, in-store shopping and stock checking, even checkouts in supermarkets.

Research carried out in 2017 on children’s screen time and mental health concluded that “moderate use of digital technology is not intrinsically harmful and may be advantageous in a connected world”. This appears to contradict the study done in 1988.

That said, there is evidence that higher levels of screen time are associated with a variety of health issues such as obesity, an unhealthy diet, depressive symptoms and a poorer overall quality of life. It would be natural to think then that limiting screen time is vital. But the key word here is “association”.

If you carried out a similar study on young people who were voracious readers of books, you could find the same association – they are more likely to be overweight as they exercise less and may have a poorer quality of life with fewer friends, or they may become unhealthily obsessed about issues they read about in the books.

So, what are we to think about the research on screen time? Overall, what the research shows is that there is no hard evidence that increased screen time will have a negative effect on children’s overall health and well-being. Moderate use, it was found, could lead to a marginal increase in well-being.

There are some well-known issues with digital screens that actively interfere with our ability to sleep. Most digital screens emit a blue light that disrupts and limits the production of a chemical in the brain known as melatonin, which helps us fall asleep.

It does make sense therefore to impose some screen time limitations, such as no screen time one hour before bedtime. The 2017 research, which was specifically designed to test for any links between well-being and screen time, tested a proposed “Goldilocks theory” – that there is a point where screen time is “just right” and can lead to a moderate increase in well-being. But what’s “just right” for one person may not be the same for everybody.

In other words, we have to use common sense.