6 - PEDIATRICS
Neuropsychiatric Disorders in Childhood
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.
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.
- 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
- Examine the long-term
effects of psychopharmacologic treatment for ADHD, especially
with psychostimulants, on sleep and sleep patterns of children
and adults with ADHD.