Objective: To perform a meta-analysis of subjective (i.e., based on questionnaires) and objective (i.e., using polysomnography or actigraphy) studies comparing sleep in children with attention-deficit/hyperactivity disorder (ADHD) versus controls.
Method: We searched for subjective and objective sleep studies (1987-2008) in children with ADHD (diagnosed according to standardized criteria). Studies including subjects pharmacologically treated or with comorbid anxiety/depressive disorders were excluded.
Results: Sixteen studies, providing 9 subjective and 15 objective parameters and including a total pooled sample of 722 children with ADHD versus 638 controls, were retained. With regard to subjective items, the meta-analysis indicated that children with ADHD had significantly higher bedtime resistance (z = 6.94, p <.001), more sleep onset difficulties (z = 9.38, p <.001), night awakenings (z = 2.15, p =.031), difficulties with morning awakenings (z = 5.19, p <.001), sleep disordered breathing (z = 2.05, p =.040), and daytime sleepiness (z = 1.96, p =.050) compared with the controls. As for objective parameters, sleep onset latency (on actigraphy), the number of stage shifts/hour sleep, and the apnea-hypopnea index were significantly higher in the children with ADHD compared with the controls (z = 3.44, p =.001; z = 2.43, p =.015; z = 3.47, p =.001, respectively). The children with ADHD also had significantly lower sleep efficiency on polysomnography (z = 2.26, p =.024), true sleep time on actigraphy (z = 2.85, p =.004), and average times to fall asleep for the Multiple Sleep Latency Test (z = 6.37, p <.001) than the controls.
Conclusions: The children with ADHD are significantly more impaired than the controls in most of the subjective and some of the objective sleep measures. These results lay the groundwork for future evidence-based guidelines on the management of sleep disturbances in children with ADHD.