"It's interesting because you might think that it's the lack of physical movement that's causing this, yet our research shows that doing homework or reading—both sedentary activities—positively contribute to well-being, so it's something else. In fact, we found that children's well-being was higher when they participated in extra-curricular activities—even if they already reported being happy.

"What this shows is that we need to find ways to encourage children of all ages and backgrounds to get involved in activities that keep them away from TV, computers and mobile devices."

The research also highlights distinct differences between children who came from low and high socio-economic backgrounds.

Students in lower socio-economic backgrounds who frequently played sports were 15% more likely to be optimistic, 14% more likely to be happy and satisfied with their life, and 10% more likely to be able to regulate their emotions.

Conversely, children who played video games and used social media almost always had lower levels of well-being: up to 9% less likely to be happy, up to 8% to be less optimism and 11% to be more likely to give up on things.

"Children who were more at risk tended to come from lower socio-economic backgrounds, which indicates a clear need for greater support in these areas," Dr. Virgara says. "As many of these children responded well to playing sports, education initiatives and continued funding of government programs such as the State Government's $100 School Sports Vouchers could be good options.

"All in all, the message is clear—gaming, watching TV, playing on computers, and scrolling through social media are not helping build or sustain positive well-being in children.

"It's certainly a challenge, especially as most children have been brought up on devices. But if families can be more aware of the issues associated with screens, then perhaps we can find a better balance of screen time and other out-of-school activities."