Sleep Physiology and Neurocognition Among Adolescents With Attention-Deficit/Hyperactivity Disorder

Objective Few studies have characterized the nature of sleep problems among adolescents with attention-deficit/hyperactivity disorder (ADHD) using polysomnography (PSG). Additionally, although adolescents with ADHD and those with sleep disturbances display similar neurocognitive deficits, the role of sleep in contributing to neurocognitive impairment in adolescent ADHD is unknown. This study investigates differences in PSG-measured sleep among adolescents with ADHD versus non-psychiatric controls (NPC) and associations with neurocognition. Method Sixty-two medication-free adolescents aged 13-17 (31 with ADHD, mean age=15.3, 50% female) completed a diagnostic evaluation, 3 nights of ambulatory PSG, the Cambridge Neuropsychological Test Automated Battery, and subjective reports of sleep and executive functioning. Linear regressions covarying for age, sex, and pubertal status examined group differences in sleep indices and partial Pearson correlations assessed relationships between sleep and neurocognition. Results Although adolescents with ADHD did not exhibit differences in PSG-measured sleep duration, awakenings, or latency (p’s>.05) compared to NPC, they displayed lower slow wave sleep percentage (β=-.40) and non-rapid eye movement (NREM) electroencephalogram (EEG) delta power (β=-.29). They also exhibited greater stage 2 percentage (β=.41), NREM EEG sigma power (β=.41), and elevated self-reported sleep disturbances (p’s<.05). Lower NREM EEG delta power, increased high frequency power, and slower decline in NREM EEG delta power overnight were associated with poorer neurocognition among adolescents with ADHD. Conclusion Adolescents with ADHD reported more sleep disturbances than NPC and exhibited differences in sleep stage distribution and NREM sleep EEG frequency. Sleep-EEG spectral indices were associated with impaired neurocognition, suggesting physiological sleep processes may underlie neurocognitive deficits in ADHD. Future studies may clarify whether sleep plays a causal role in neurocognitive impairments in adolescent ADHD and whether interventions normalizing sleep improve neurocognition.