Many teenagers experience sleep issues linked to their biological clocks rather than clinical insomnia, prompting a need for tailored treatment approaches that recognise delayed sleep-wake phase disorder.
Sleep problems are common in adolescence, but not every teenager who struggles to fall asleep has insomnia in the clinical sense. As Professor Francisco Musich argues in a blog for the Association for Child and Adolescent Mental Health, puberty brings a natural shift towards later sleep and waking times, and that biological change can clash with early school starts and other demands. In that setting, a young person may look tired, report difficulty getting to sleep and struggle in the morning, yet the underlying issue may be a delayed body clock rather than insomnia disorder.
That distinction matters because insomnia and delayed sleep-wake phase disorder are treated differently. Insomnia is usually marked by persistent trouble falling asleep or staying asleep despite enough opportunity for rest, while delayed sleep timing is fundamentally a timing problem: sleep occurs later than school, work or family schedules allow. In adolescents, the two can overlap, which is why questionnaires alone can be misleading. The Bergen Insomnia Scale is a useful screening tool, but it cannot by itself explain why a teenager is sleeping badly or whether the main problem is chronic insomnia, circadian delay or a mixture of both.
A recent study of 3,867 Norwegian high school pupils illustrates the point. Using the Bergen Insomnia Scale, researchers found that 34.5% met operational criteria for insomnia, and the figure was higher among girls than boys. Yet among those who screened positive, 88.4% also reported at least one sign of circadian delay, such as difficulty waking for school, sleeping late when free to do so or oversleeping on school days. Around 15.5% showed all four markers examined in the study. Those students also tended to have later sleep timing, greater eveningness, about six hours of sleep on school nights, roughly eight and a half hours on free days and nearly three hours of social jetlag, the gap between biologically preferred sleep and socially imposed schedules.
For clinicians, parents and schools, the practical message is to look beyond the label of insomnia and ask what happens when an adolescent is allowed to sleep on their own schedule. If sleep becomes much easier when bedtime is pushed later, or if weekends bring substantial catch-up sleep, circadian delay may be a better explanation than insomnia. That distinction can change treatment: cognitive behavioural therapy for insomnia is the standard approach for true insomnia, but delayed sleep timing often calls for carefully timed morning light, steadier wake times, behavioural changes and sometimes melatonin-based strategies. The broader lesson is that many sleep complaints in teenagers are not simply about poor sleep habits, but about a biological clock that no longer matches the school day.
Disclaimer: This content is for informational purposes only and is not intended to be a substitute for professional medical judgment, advice, diagnosis, or treatment.
