Last week saw media reports stating that, alarmingly, almost 40% of New Zealand teenagers have a sleep disorder. This stemmed from a Royal New Zealand College of General Practitioners press release, and a paper published in the Journal of Primary Health Care. At face value, these findings are very concerning indeed.
The study surveyed 1388 Auckland high school students, from six different schools, using the authors’ Auckland Sleep Questionnaire. Drawing from the International Classification of Sleep Disorders, this questionnaire aims to assess a number of sleep problems commonly seen in primary care, and their potential underlying causes. An algorithm is then used to diagnose insomnia, obstructive sleep apnoea, parasomnias, delayed sleep phase disorder, medical problems, substance problems, and mood disorders.**
As an example, the criteria used to determine whether an individual has a sleep problem are outlined below. These are not unreasonable and for the most part describe the broad criteria used to diagnose insomnia.
Do you have problems getting to sleep, staying asleep or waking early such that it affects your work function the next day? This includes feeling excessively sleepy the next day for the duration of at least one month.
The study found that 37% of teenagers reported ‘significant sleep symptoms’ lasting more than a month. Depression and anxiety are cited as the main contributor of sleep problems in teenagers, and alcohol as a significant contributor. The relationships between depression and anxiety and sleep problems are well established, and modest correlations were observed here. However, unfortunately the authors have assumed causal relationships based on relatively high prevalence rates for alcohol use in this group of teenagers (or at least alcohol as an independent predictor is not reported).
There is no question that sleep among New Zealand teenagers is a significant concern. Large population studies of New Zealand teenagers have shown that approximately 21% of New Zealand teenagers do not get enough sleep (8-9 hours rather than the recommended 9-10). There is also a large discrepancy between bedtimes on school nights (10.30pm) compared with weekends (midnight). However, significant contributors to this are changes to the biological clock seen during adolescence, growing independence and the increasing use of light-emitting technology in the evening (I’ve blogged about this before).
If 37% of New Zealand teenagers have a sleep problem, where to from here? There is little New Zealand data from which to design strategies for improving sleep health in teenagers, and unfortunately this study does not advance our ability to do so. Taking into account other known contributors to sleep disturbance in adolescence may have provided greater understanding of the extent of some of the behavioural (and physiological) factors that can lead to sleep problems. These may have included sleep duration, which is a known risk factor for poor daytime functioning and parasomnias. Additionally, those with an irregular sleep schedule (and no sleep disorder) may have trouble getting to sleep when they want to. Teenagers who are required to wake early on school days may feel like they have to wake earlier than they would like and consequently feel sleepy during the day. These patterns can exist irrespective of the presence of any sleep disorder, including delayed sleep phase disorder.
A focus on diagnosing sleep disorders may take our focus away from where it needs to be. There is great potential to improve teenagers’ sleep in primary care with thorough understanding of the expected changes in sleep seen in this age group, as well as awareness of the prominent issues. This would allow tailored, effective promotion of strategies teenagers can use to achieve good sleep health.
**The authors have identified many of the limitations of this study. Notably, the questionnaire has been validated in adults against subjective assessments by an experienced sleep clinician. It should be noted that for disorders that are normally objectively assessed, such as obstructive sleep apnoea, this questionnaire only provides an indication of potential risk.