ADELAIDE, Australia — The monsters keeping our kids up at night aren’t cartoon characters—they’re made of pixels and social media likes. A comprehensive study reveals a worrying trend: late-night phone use is turning bedtime into a battleground for sleep and mental health. Research from Australia reveals a worrying link between late-night texting, cyberbullying, and psychological distress in children as young as seven.

The childhood rite of passage of staying up past bedtime has taken a dark turn in the digital age, researchers say. The study, published in the journal Teenagersanalyzed data from more than 53,000 Australian children aged seven to 19. For many children, “lights out” is just the beginning of their nighttime online activities — and the consequences go beyond feeling sleepy the next day.

Data collection took place between March and December 2019, using a questionnaire examining various aspects of resilience and well-being. The survey included demographic items, risk and protective behavior items, and optional risk behavior items.

To understand how kids were feeling, researchers used a special set of questions called the PHQ-4. It asked kids whether they felt nervous, worried, sad, or uninterested. Their answers ranged from “Never” to “Almost every day.”

Other questions included how often children used their phones at night, how well they slept, or whether they had been bullied online. For example, they asked whether children slept eight hours most nights and how many times they sent messages on their phones late at night. They also asked whether children had been bullied at school recently.

One of the most striking findings was that around a third of primary school children (aged 7–11) and over 60% of secondary school children (aged 12–19) reported using their phones at night at least once a week. This nighttime phone use was associated with shorter sleep duration and increased psychological distress across all age groups.

But it’s not just about losing sleep. The study also found that kids who experienced cyberbullying were more likely to use their phones at night and report sleep and psychological problems. About 15% of kids surveyed had experienced cyberbullying in the previous school term, with rates peaking in early adolescence.

“Adolescents are at greater risk for socio-emotional disorders because they are at a stage of development where they are less prepared cognitively, behaviorally, and neurobiologically,” study co-author Dr. Stephanie Centofanti, a researcher at the University of South Australia, said in a statement.

Centofanti and her team used a clever approach to investigate the relationship between nighttime phone use, cyberbullying, sleep, and psychological distress. They tested whether nighttime phone use might exacerbate the negative effects of cyberbullying on sleep and mental health.

Interestingly, the results showed some unexpected patterns. For boys, especially those in high school, using their phones at night did indeed worsen the psychological distress associated with cyberbullying. But the effect was stronger for boys who had not experienced cyberbullying. The researchers suggest that this may be due to a “ceiling effect”—children who had been cyberbullied already reported such high levels of stress that there wasn’t much room for it to increase any further.

In terms of sleep, nighttime phone use was found to exacerbate the negative impact of cyberbullying on sleep quality for both boys and girls across all age groups. Again, this effect was surprisingly stronger for children who had not experienced cyberbullying.

The study’s findings aren’t as simple as saying “phones are bad.” Instead, the research points to the need for better approaches to managing children’s digital device use, especially at night.

For parents, educators, and health care providers, this study reinforces the importance of addressing nighttime phone use as part of overall strategies to improve children’s sleep and mental health. This could include establishing household rules around screen time after bed, educating kids about the importance of sleep, and being alert for signs of cyberbullying.

“It is clear that parents need to pay more attention to managing smartphone use at night, especially if their children are more susceptible to cyberbullying, and make sure their children get enough sleep,” says Dr Centofanti.

As our world becomes increasingly digital, understanding how technology impacts our children’s well-being is more important than ever. This study provides valuable insights that can help shape healthier digital habits for the next generation.