Mental health problems in adolescents with delayed sleep phase: results from a large population‐based study in Norway

The aim of the current study was to compare mental health problems, resilience and family characteristics in adolescents with and without delayed sleep phase (DSP) in a population‐based sample. Data were taken from the youth@hordaland‐survey, a large population‐based study in Hordaland County in Norway conducted in 2012. In all, 9338 adolescents aged 16–19 years (53.5% girls) provided self‐reported data on a wide range of instruments assessing mental health symptoms, including depression, anxiety, obsessive–compulsive behaviours, attention deficit hyperactive disorder (ADHD) symptoms, perfectionism, resilience and sleep. Measures of socioeconomic status were also included. Three hundred and six adolescents (prevalence 3.3%) were classified as having DSP [according to the International Classification of Sleep Disorders‐2 (ICSD‐2)] criteria. Adolescents with DSP reported higher levels of depression, anxiety and ADHD symptoms. Adolescents with DSP also exhibited significantly lower levels of resilience. The Cohen's d effect sizes ranged from small [obsessive–compulsive disorder (OCD): d = 0.15] to moderate (inattention: d = 0.71). In the fully adjusted model, the significant predictors of DSP included inattention [odds ratio (OR): 2.11], lack of personal structure (OR: 2.07), low (OR: 1.85) and high (OR: 1.91) paternal education, parents not living together (OR: 1.81), hyperactivity/inattention (OR: 1.71) and poorer family economy (OR: 1.59). In conclusion, the high symptom load across a range of mental health measures suggests that a broad and thorough clinical approach is warranted when adolescents present with DSP.