This study followed adolescents in Norway who took part in the population-based youth@hordaland survey. It linked their answers to health registry records. The researchers had usable sleep data for 9,007 teens. Just over half were girls (53.4%), and the average age was 17.4 years, ranging from 16 to 19. About 1 in 10 (911 teens) had been in contact with child and adolescent mental health services. This was the clinical group. The rest formed a comparison group.
Sleep problems showed up across all the psychiatric disorders, not just one or two. Insomnia was reported by 16.7% of the comparison group. In the clinical group it was more common, from 28.7% among those with ADHD to 48% among those with depression. A pattern of going to sleep and waking much later than usual (delayed sleep phase) was reported by 2.9% of the comparison group. In the clinical group it ranged from 0% for eating disorders up to 20% for conduct disorder. Every diagnostic group spent, on average, less than 85% of their time in bed asleep. Even so, only 0.6% of those in services had a formal sleep disorder diagnosis on record. Because the data came from one point in time, the study cannot say which came first.
Source: Mari Hysing, Ove Heradstveit, Allison G. Harvey, et al.. Sleep problems among adolescents within child and adolescent mental health services. An epidemiological study with registry linkage. European Child & Adolescent Psychiatry (2020). doi:10.1007/s00787-020-01676-4