Background: Sleep may underlie psychiatric symptoms in young children. However, not many studies have reported on sleep and its associations with symptoms in young child psychiatric patients. Objectives: To assess the amount and quality of sleep and how sleep associates with psychiatric symptoms in young child psychiatric patients. Furthermore, we evaluated how sleep and daytime somnolence differed in patients and their age- and gender-matched controls. Method: The sample consisted of 139 3- to 7-year-old child psychiatric outpatients and 139 age- and gender-matched controls from community. We evaluated sleep and daytime somnolence with the Sleep Disturbance Scale for Children in all children and psychiatric symptoms with Child Behaviour Checklist (CBCL) in the patient group. Family background information was collected from the patients. Results: Of the patients, 31.6% had a significant sleep problem and 14.4% slept too little. The most typical sleep problems were restless sleep (31.7%), morning tiredness (21.6%) and difficulties getting to sleep at night (18.7%). All types of sleep problems were associated with CBCL total, internalising and externalising problems (all p-values < .01). We observed a strong association between all types of sleep problems and emotionally reactive subscale ( p-value < .001). Furthermore, parent-reported sleep problems increased significantly the risk of having high scores on total (odds ratio (OR) = 5.3, 95% confidence interval (CI) = [2.2, 12.6], p < .001), external (OR = 3.7, 95%, CI = [1.6, 8.5], p < .01) and internal (OR = 2.5, 95% CI = [1.1, 5.5], p < .05) scores after controlling for age, gender, family structure and parent’s educational level. Even mild sleep disturbance increased the intensity of psychiatric symptoms. Compared to controls, patients slept less ( p < .001) and had significantly more frequent restless sleep, nightmares and morning and daytime somnolence. Conclusion: Sleep problems and too little sleep are prevalent in young child psychiatric patients, and they relate strongly to the intensity of psychiatric symptoms. Identification and treatment of sleep problems should be a routine part of the treatment plan for young child psychiatric patients. The results emphasise the need for assessing sleep in young child psychiatric patients, as treating the sleep problem may reduce psychiatric symptoms.
