SECTION 6 - PEDIATRICS

Neuropsychiatric Disorders in Childhood and Sleep

Background

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common psychiatric disorders in childhood, affecting some 5 to 10% of children. The etiology of sleep disturbances observed in association with ADHD is likely to be multi-factorial and to vary among patients. In addition to medication-related sleep effects and the influence on sleep behavior of such common co-morbid conditions as oppositional defiant disorder, depression, and anxiety disorders, the primary sleep disorders such as SDB and Restless Legs Syndrome/Periodic Limb Movement Disorder (RLS/PLMD) may present with "ADHD-like" symptoms or exacerbate underlying ADHD. Primary abnormalities in central nervous system (CNS) regulation of arousal, behavioral inhibition and self-regulation, and/or vigilance associated with ADHD have also been postulated to result in sleep disturbances, suggesting a more primary or fundamental sleep-wake dysregulation in at least some children. There is considerable evidence to suggest that brain systems regulating sleep and attention/arousal are linked, and that abnormalities in similar neurotransmitters such as the noradrenergic and dopaminergic systems may be found in ADHD and in sleep disturbances. These relationships are at present still poorly understood.

Progress In The Last 5 Years

- Studies of children with ADHD have examined the relationship between sleep architecture, sleep patterns and behaviors, and sleep disturbances and ADHD. When using primarily parental (or self-report) surveys or polysomnography (PSG), the results have been mixed and at times contradictory. While most "objective" studies have not found consistent significant differences in sleep architecture and patterns between children with ADHD and controls, most parental report studies have reported sleep problems including difficulty falling asleep, night wakings and restless sleep in children with ADHD. These consistent discrepancies between parental and more objective sleep measures remain an important research and clinical question. In addition, there are a number of methodological concerns with many of these studies, including small sample sizes and selection bias, variability in diagnostic criteria for ADHD, variability in defining the control groups, and failure to consider the effects of potential confounders such as diagnostic subgroup of ADHD, medication status, the presence of co-morbid psychiatric conditions, and age. Virtually no studies have examined sleep disturbance in adolescents and young adults with ADHD.

- Studies have examined the complex relationship between primary sleep disorders such as SDB and PLMD, and the constellation of neurobehavioral symptoms that comprise the syndrome of ADHD (inattention, hyperactivity, impulsivity, executive function impairment).

- Some small studies have explored the use of medications such as clonidine for sleep disturbances associated with ADHD, but no systematic studies of behavioral and/or clinical trials of pharmacologic treatment have been conducted.

Research Recommendations

- Examine the neuroanatomical and neurophysiologic relationships between regulation of sleep and of attention and arousal, including the roles of the noradrenergic, dopaminergic, and other neurotransmitter systems. Develop animal models that present phenotypes associated with ADHD.

- Describe the scope and magnitude of sleep disturbances present in children and adolescents with ADHD compared to the general population, including the natural history of sleep disturbances as ADHD progresses into adolescence and adulthood. Describe the impact of ADHD on morbidity, including adverse behavioral outcomes such as injuries and motor vehicle crashes, substance abuse, and academic failure. Describe the risks and protective factors for sleep disturbances in children and adolescents with ADHD, and the impact of potential confounders such as co-morbid psychiatric disorders and ADHD medication use.

- Examine the relationships and clarify directionality between primary sleep disorders such as SDB and RLS/PLMD, and symptoms of hyperactivity and inattention in children and adolescents. Prevalence studies of primary sleep disorders in children diagnosed with ADHD are also needed.

- Evaluate the efficacy of various treatment modalities for sleep problems in ADHD, including behavioral interventions and pharmacotherapy, and the impact of treatment on the natural history of the disorder into adulthood.

- Examine the long-term effects of psychopharmacologic treatment for ADHD, especially with psychostimulants, on sleep and sleep patterns of children and adults with ADHD.