Case reports of sleep phenotypes of ADHD: from hypothesis to clinical practice

Restless legs syndrome and iron deficiency in adults with attention-deficit/hyperactivity disorder

STUDY OBJECTIVE

The association between restless legs syndrome (RLS), periodic leg movements during sleep (PLMS) and iron deficiency has been reported in children with attention-deficit/hyperactivity disorder (ADHD); however little is known in adults. The aim of this study was to assess frequencies of RLS, PLMS and other leg movements (LM) and iron deficiency and their relationships with ADHD phenotype in adults with ADHD.

METHODS

Two hundred adults with ADHD (112 males, median age 31 years) were evaluated on lifetime ADHD symptoms and sleep characteristics. RLS was diagnosed according to standard criteria. Serum ferritin levels were measured, with iron deficiency defined as <50 ng/mL. A subgroup of 48 ADHD patients with RLS, 48 ADHD without RLS and 48 controls underwent a polysomnography to record sleep, LM, and PLMS.

RESULTS

RLS was diagnosed in 33.0%, associated with earlier onset of ADHD, hyperactive presentation and more severe lifetime ADHD symptoms. Iron deficiency was found in 35.5% with higher frequency in patients with RLS. LM were more frequent in ADHD patients, with higher LM periodicity levels in those with comorbid RLS in comparison to controls. However, PLMS index did not differ between groups. Patients with ADHD and RLS had higher frequency of iron deficiency than other groups.

CONCLUSIONS

In a large sample of adults with ADHD, we individualized a subgroup characterized by earlier and severe ADHD symptoms, RLS, higher LM during sleep and iron deficiency. This endophenotype may reflect a different neurobiological mechanism that remains to be further studied.

Headache and ADHD in Pediatric Age: Possible Physiopathological Links

Primary headache and attention-deficit/hyperactivity disorder (ADHD) are common disorders in children and adolescences, frequently associated to severe cognitive, emotional, and behavioral impairments. They both are a disabling condition with consequences on family and child's quality of life. Literature data on their association are contrasting. Dopaminergic system dysfunction, brain iron deficiency, and sleep disturbance should be considered to better understand headache and ADHD overlap. In this review, we analyze the complex association between these two diseases and the potential impact on child neurodevelopment.

Associations of sleep disturbance with ADHD: implications for treatment

Attention-deficit/hyperactivity disorder (ADHD) is commonly associated with disordered or disturbed sleep. The relationships of ADHD with sleep problems, psychiatric comorbidities and medications are complex and multidirectional. Evidence from published studies comparing sleep in individuals with ADHD with typically developing controls is most concordant for associations of ADHD with: hypopnea/apnea and peripheral limb movements in sleep or nocturnal motricity in polysomnographic studies; increased sleep onset latency and shorter sleep time in actigraphic studies; and bedtime resistance, difficulty with morning awakenings, sleep onset difficulties, sleep-disordered breathing, night awakenings and daytime sleepiness in subjective studies. ADHD is also frequently coincident with sleep disorders (obstructive sleep apnea, peripheral limb movement disorder, restless legs syndrome and circadian-rhythm sleep disorders). Psychostimulant medications are associated with disrupted or disturbed sleep, but also ‘paradoxically’ calm some patients with ADHD for sleep by alleviating their symptoms. Long-acting formulations may have insufficient duration of action, leading to symptom rebound at bedtime. Current guidelines recommend assessment of sleep disturbance during evaluation of ADHD, and before initiation of pharmacotherapy, with healthy sleep practices the first-line option for addressing sleep problems. This review aims to provide a comprehensive overview of the relationships between ADHD and sleep, and presents a conceptual model of the modes of interaction: ADHD may cause sleep problems as an intrinsic feature of the disorder; sleep problems may cause or mimic ADHD; ADHD and sleep problems may interact, with reciprocal causation and possible involvement of comorbidity; and ADHD and sleep problems may share a common underlying neurological etiology.

Headache and attention deficit and hyperactivity disorder in children: common condition with complex relation and disabling consequences

The aim of this review was to analyze literature data on the complex association between headache and attention deficit and hyperactivity disorder (ADHD) in children, in order to explore its possible consequences on child neurological development. Headache and ADHD are two common conditions in the pediatric population. They both are disabling diseases that impact the child's quality of life and are associated with severe cognitive, emotional, and behavioral impairments. To assess and analyze literature data about the association of ADHD and headache in children and possible physiopathogenesis relationships, we searched for the following terms: headache, migraine, tension-type headache, ADHD, and children (MESH or text words). We found different studies that assess the clinical, epidemiological, and physiopathogenetic overlap between these two diseases, with contrasting results and unresolved questions. Structural and functional abnormalities in brain networks have been found to be central in both headache and ADHD pathophysiology. It will be crucial to gain a better understanding of how subcortical-cortical and corticocortical network development is altered during the onset of the disorders.

Sleep problems and their effect in ADHD

Sleep problems are common in attention-deficit/hyperactivity disorder (ADHD) to the extent that they mimic or exacerbate daytime symptoms expression. In this review, we advocate the need for a better understanding of sleep alterations in youths with ADHD and their impact on neurobehavioral functions including learning, memory and emotional regulation. An in-depth exploration of existing data showed that although extensively studied, the actual nature of sleep problems in ADHD and their effects on daytime behavior are still less well understood. Important issues, among which developmental changes in sleep architecture and role of subtle sleep electroencephalogram signatures, are generally neglected. Future research of sleep effects on behavior in ADHD would benefit from considering developmental aspects and links between brain activation patterns during sleep and wake.