Researchers in South Korea surveyed 48,829 teenagers to understand why some develop problematic smartphone use (compulsive phone habits that interfere with daily life) while others don't. They wanted to know whether poor sleep plays a role, and if so, how.
The study categorised teens into three groups: general users (72.1%), potential-risk users (24.8%), and high-risk users (3.1%). High-risk users averaged 7 hours of daily smartphone time—far more than the other groups.
Poor sleep pushes teens toward heavier phone use
Teens who reported low sleep satisfaction were significantly more likely to develop problematic smartphone use. This wasn't a tiny effect: the study found that sleep dissatisfaction was one of the clearest predictors of unhealthy phone habits. Interestingly, girls were at higher risk than boys, and teens using phones for 4+ hours daily were particularly vulnerable.
Anxiety and loneliness are the hidden link
The researchers discovered why poor sleep leads to phone addiction. When sleep is unsatisfying, teens experience more anxiety and loneliness—and these emotions drive them to their phones. The analysis showed that anxiety accounted for 30% of the link between poor sleep and problematic phone use, while loneliness accounted for 15.2%. In other words, a tired, anxious, lonely teen reaches for their phone as a coping tool, not just by chance.
Physical activity and perceived health matter too
Teens who were physically inactive and reported poor health alongside poor sleep faced the highest risk. This suggests the problem isn't isolated to sleep alone—it's part of a broader picture of wellbeing.
A note on scope: This study was conducted in South Korea with a large sample, making the findings robust. However, it shows correlation, not proof that poor sleep directly causes phone addiction; other factors may play a role. The findings likely apply to Singapore teens given similar lifestyles and access to technology, though local research would confirm this.
What to focus on if your teen's phone use concerns you
- Prioritise consistent sleep routines; better sleep may naturally reduce anxiety-driven phone reaching.
- Notice if poor sleep, phone use, and loneliness or anxiety are clustering together in your teen.
- Encourage physical activity alongside sleep improvements, as both were linked to lower risk.