Sleep patterns in children with ADHD: a population-based cohort study from birth to 11 years.

Associations between sleep duration and disturbance in infancy and early childhood and attention deficit hyperactivity disorder diagnoses were investigated. Data from the Avon Longitudinal Study of Parents and Children, a population-based prospective longitudinal birth-cohort study of children born in 1991-1992 in South-West England, were employed. Eight thousand, one hundred and ninety-five children were assessed using the Development and Well-Being Assessment. One hundred and seventy-three cases (2.1%) met criteria for attention deficit hyperactivity disorder. Parental report at eight time points showed children with attention deficit hyperactivity disorder slept less than peers. Absolute differences were small and mainly restricted to night-time sleep, with no strong evidence of differences from controls, except at 69 months [5 years 9 months; 12 min (95% CI: 5-19), P = 0.001], at 81 months [6 years 9 months; 15 min (95% CI: 8-22), P < 0.001] and at 115 months [9 years 7 months; 11 min (95% CI: 4-18), P = 0.001]. The attention deficit hyperactivity disorder group had more night-waking at every age, significant from about 5 years. When tracking children's sleep along a normative centiles chart, a shift in sleep duration from one centile to a lower centile was a useful predictor of attention deficit hyperactivity disorder. Age-specific decreases of >1SD in sleep duration across adjacent time points was a significant predictor of attention deficit hyperactivity disorder at 3-5 years (P = 0.047). In children with attention deficit hyperactivity disorder, shorter sleep duration and sleep disturbances appear early and predate the usual age of clinical diagnosis. The rate of change of sleep duration relative to an individual, rather than absolute sleep duration at any stage, may prove beneficial in identifying increased risk of attention deficit hyperactivity disorder.

Sleep patterns in children with autistic spectrum disorders: a prospective cohort study.

OBJECTIVE: To investigate longitudinal sleep patterns in children with autistic spectrum disorders (ASDs). STUDY DESIGN: Prospective longitudinal study using Avon Longitudinal Study of Parents and Children, an English cohort born in 1991-1992. Parental reports of sleep duration were collected by questionnaires at 8 time points from 6 months to 11 years. Children with an ASD diagnosis at age 11 years (n=73) were identified from health and education records. RESULTS: From aged 30 months to 11 years old, children with ASD slept for 17-43 min less each day than contemporary controls. No significant difference in total sleep duration was found in infancy, but from 30 months of age children with ASD slept less than their peers, a difference that remained significant after adjusting for sex, ethnicity, high parity and epilepsy. The reduction in total sleep was wholly due to changes in night rather than daytime sleep duration. Night-time sleep duration was shortened by later bedtimes and earlier waking times. Frequent waking (3 or more times a night) was also evident among the children with ASD from 30 months of age. Age-specific decreases of >1SD within individuals in sleep duration across adjacent time points was a predictor of ASD between 18 months and 30 months of age (p=0.04) and from 30 months to 42 months (p=0.02). CONCLUSIONS: Sleep duration in children with ASD is reduced from 30 months of age and persists until adolescence.

Childhood sleep duration and associated demographic characteristics in an English cohort.

STUDY OBJECTIVES: To provide reference data on sleep duration throughout childhood and explore the demographic characteristics associated with sleep. DESIGN: Population-based prospective longitudinal birth-cohort study. SETTING: South-West England, children born in 1991-1992 and followed since birth. PARTICIPANTS: Eleven thousand five hundred children with repeat measures of sleep from birth based on parent-reported questionnaires. Data on daytime and nighttime sleep duration and timings and night awakenings at 8 timepoints from age 6 months to 11 years. RESULTS: Total sleep duration steadily fell from 13 hours and 12 minutes during infancy to 9 hours and 49 minutes at 11 years of age. Compared with earlier studies, the younger children in this cohort slept for a shorter period. The variation in sleep duration was very wide: from 10 to 17 hours in early infancy, narrowing to 8.5 to 11 hours at 11 years. Half of the children at preschool age woke at least once during the night, but frequent waking (> 3 times) peaked in infancy (10% of all infants) and steadily declined in the preschool-aged years. Despite going to bed at the same time, girls slept consistently longer than boys (by 5-10 minutes). Children from low-income families went to bed later and woke up later, but there was little difference in total sleep duration. Children of younger mothers (< 21 years) slept longer, whereas children of older mothers (> 35 years) slept persistently less. Children in larger families tended to go to bed later, as did the minority group of non-White children in the cohort. CONCLUSIONS: Given the wide natural variation of sleep in the childhood population, any recommendations on optimal sleep duration at any age must take into account considerable individual variability.