journal adhd

7/30/2019 Journal ADHD

1/11

Introduction

The relationship of attendon-deficit/hyperactivity disorder (ADHD)with sleep-related disorders has received remarkable interest. Thecomorbidity warrants close attention since sleep-related disordersimpinge on the same functional domains as those impaired inADHD, such as sustained attention, inhibition, and workingmemory. Hence, it has been alleged that sleep-related disordersmight possibly lead to an aggravation or mimicry of the symptomsofADHD. A second reason for the interest is that stimulants, thetreatment of first choice for ADHD, are notorious for theirdeleterious effect on sleep.

A vast number of studies on the issue ofsleep in ADHD has recentlybeen published, including several reviews1-3 and book chapters.4,5However, a clear overview of the recent findings with a focus on theclinical implications is yet missing. The present review discussesstudies published after the date of the introduction of DSM-IV.6 Thesleep disorders that have been linked to ADHD are discussedseparately. First, elementary methodological aspects ofsleepassessment are summarized.

Assessment ofSleep

Polysomnography (PSG) is considered to be the gold standard insleep research. It usually records 2 or more electrophysiologicalmeasures such as electroencepalography (EEG) andelectromyography (EMG). Consequently, PSG permits assessment ofsleep architecture. PSG is relatively expensive and often requirespeople to sleep in laboratory settings, which is known to potentiallychange habitual sleep patterns and induce a lower sleep efficiencyat the first night of the sleep laboratory measurements: the "first-night effect".7,8 In practice it is usually not possible to make PSGregistrations during more than 2 consecutive nights.

Actigraphy assesses physical motion with an actiwatch, a smalldevice with the size of a normal wristwatch, which stores theresulting information. Actigraphy can be performed during manyconsecutive days and nights. Several studies have indicated that forhealthy subjects the agreement rates between actigraph-based andPSG-based minute-by-minute sleep-wake scoring are above 90%;9-13 however, its accuracy in estimating sleep reference times (e.g.,sleep onset time, time of awakening) is only moderate. Theaccuracy of actigraphy declines as the quality and quantity ofsleepdiminish, such as for patients with sleep-related disorders13-15 andmajor depression.16 PSG and actigraphy measure sleep more orless objectively.


2/11

Subjective methods ofsleep assessment can be obtained directlyfrom subjects themselves by means of a clinical history, sleepquestionnaires, or sleep logs. In case subjects themselves are notable to supply the information needed, bedpartners or parents arerequested to record the information. The validity and reliability of

sleep questionnaires and sleep logs are debateable. Research hasrevealed that people are not accurate assessors of their own sleepbehavior, nor are they for the sleep of someone else.17 Sleepquestionnaires and sleep logs are frequently used for intraindividualcomparisons, e.g., to assess treatment effects.

Breath-related Sleep Disorders

Breath-related sleep disorders (SDB) (Table 1 ) are often associatedwith behavioral problems that show much similarity tocharacteristics ofADHD.18-21 Although hyperactivity is often shownat referral in children with suspected SDB, it is not displayed moreoften in children with a PSG-confirmed diagnosis of SDB.22

Children with diagnosed ADHD do not significantly more often showsymptoms of SDB when assessed with 1 or 2 items in aquestionnaire.23-26 When assessed with a questionnairecomprising 6 snoring- and SDB-related items, children with ADHDshow elevated scores as compared to psychiatric controls.27However, 3 recent PSG studies have found the presence of SDB inADHD to be negligible.28-30

PSG studies have demonstrated that the complaints of SDB, whichare often ventilated by parents ofADHD children, can often not beconfirmed on investigation.28,29 Such discrepancies betweenparental and objective measures have also been found for othersleep problems in ADHD, as will be discussed later.

To summarize, attention deficit and behavioral problems can often

be found in children with SDB. Children with ADHD often havesymptoms of SDB, as reported by their parents. However, objectivestudies do not support that SDB occurs more often in ADHD.

Treatment

Adenotonsillectomy is the first line of treatment, and continuouspositive airway pressure is an option for those who are notcandidates for surgery or do not respond to surgery (for clinicalpractice guidelines, see reference 31). Treatment of SDB

establishes a significant reduction in aggression, inattention, andhyperactivity, 32-34 and in case of concurrent ADHD normalizes


3/11

typical electrophysiological features ofADHD.35 Case reports havebeen published of patients in whom a diagnosis ofADHD had beenmade formerly but who after treatment for SDB could be weanedfrom methylphenidate.36 Therefore, treatment of SDB in ADHDshould first be focussed on SDB. Stimulant treatment for ADHD is

not likely to affect SDB severity.29

Motor Restlessness During Sleep

Before 1980, reports of high nocturnal activity in hyperactivechildren were so common that the American Psychiatric Associationdecided to enclose it in the criteria of attention deficit disorder in

the DSM-III.37 This criterion was omitted in later revisions of thediagnostic manual.

Indeed, several parental observation studies demonstrated thatchildren with ADHD show higher levels of activity during their sleepor have more restless sleep than controls.19,24,25,29,38,39 Thishas been confirmed by studies using more objective methods suchas actigraphy or infrared camera recordings.40,41 PSG showed ahigh frequency of short movement-related epochs in children withADHD; however, the total time of movements was not elevated ascompared to normal controls.30

Motor restlessness during sleep can be a manifestation of a periodiclimb movement disorder (PLMD) (Table 1). Hyperactivity andinattention have been found to be increased in children withPLMD.42 Another study revealed significantly correlated PLMD andADHD scores, which were both assessed with questionnaires.21

Whether children with ADHD show increased PLMs has been studiedextensively. They were found to show significantly more often PLMDas compared to normal controls.30,43,44 Others revealed that it isnot the number of PLMs per se, but rather the number of PLMs that

are associated with arousals that is increased in children withADHD. However, this was the case in children with ADHD who werereferred to a sleep clinic, but not in children with ADHD who wererecruited in a community survey.38,42 Two recent studies showedno increased indexes of PLMs in children with ADHD but found thehighest PLM indexes in the ADHD group.19,29 However, in these 2studies no formal DSM-IV diagnosis ofADHD was made.

Restless legs (Table 1) has also been studied in association withADHD. These studies indicated that symptoms ofADHD,45 but notADHD itself as a disorder,27 were related to restless legs syndrome(RLS).


4/11

The overall conclusion is that there is ample support that childrenwith ADHD show increased motor restlessness during sleep.Whether these movements are manifestations of PLMD/RLS remainsunresolved since the results on this issue are very inconsistent. Theinconsistency of findings might have resulted from the differences in

ADHD diagnosis, which has been mentioned previously. Stimulantuse was found not to be related to PLMD in ADHD29,43 and,therefore, is unlikely to have played a role in the inconsistency.

Assertions have been made that ADHD and PLMD might begenetically linked with the dopaminergic system as commonfactor.41,44 As yet, no studies have addressed this genetic issue.

Treatment

Treatment of RLS or PLMD in children with ADHD should begin withstandard treatment strategy, which is the alleviation of any diseasesor deficiencies underlying the RLS or PLMD and improvement ofsleep hygiene if possible.46 The pharmacologie therapy that is beststudied and most successful is use of dopaminergic agents.46,47However, these have been studied in only a few children.Dopaminergic therapy in 7 children with PLMD and comorbid ADHDimproved symptoms of PLMD as well as those ofADHD in all

children.48 The tolerability of dopaminergic agents (modafinil)combined with methylphenidate (8 hours after modafinil) was good
http://search.proquest.com/textgraphic/200038055/TextPlusGraphics/137F101EC92469EDE43/8/1?accountid=49910


5/11

in healthy volunteers.49 The effect of stimulant treatment on motorrestlessness during sleep is negligible.29

Insomnia

Patients with ADHD often experience difficulties with settling andfalling asleep, such as in insomnia (Table 1). This has beenconfirmed by many studies using insomnia items on parentquestionnaires. 19,23-26,38,39,50-52 One such study failed to finda relationship between ADHD and parental ratings ofsleep onsetproblems.40 Studies in which parents were asked to record sleeponset, latency, or duration revealed no differences between children

with ADHD and controls.29,50,53

Studies of insomnia in ADHD have also been done with objectivemeasures such as polysomnographyia.19,38,41,54 andactigraphy,40,52,53 None of these revealed significant differencesbetween children with ADHD and controls in sleep onset time, sleeplatency, or sleep duration.

Summarizing, it seems that parents of children with ADHD are morelikely to experience sleep onset problems than other parents. Thepresence of such problems is not supported by studies comparingaverage sleep onset/offset times of children with ADHD and

controls. This discrepancy is not due to incongruence betweensubjective and objective methods. Rather, it seems to be due to adifference in how parents are asked to assess their child's sleepproblems: by means of retrospective ratings of insomnia or byprospective assessments ofsleep reference times (both subjective).Studies in which both were measured resulted in significantretrospective results and no significant prospectiveresults.19,25,50,52 An explanation for this discrepancy could be thehigh variance ofsleep onset and offset found in ADHD,53,55 whichpossibly results in sleep onset problems on several days in theweek. Such a weekly sleep pattern might lead to statisticallysignificant results when parents are asked for the presence ofsleeponset problems, but not, however, when sleep onset/offset timesare averaged over the week.

Treatment

In American pediatrics, the prescription ofsleep medication inchildren with ADHD is 2- to 4fold greater as compared to non-ADHDchildren.56 This might indicate that in children with ADHDbehavioral practices are harder to apply. One of the reasons isprobably that in a substantial number of cases the insomnia is


6/11

caused or aggravated by the treatment ofADHD withstimulants,26,57-60 although 1 study found no effects of stimulantson polysomnographically assessed sleep latency and total sleepduration.29 The efficacy of melatonin in combination withmethylphenidate for the treatment of insomnia seems promising

and safe.61

Disturbed Sleep Architecture

Many studies have focused on sleep architecture disturbances(Table 1) in ADHD before the introduction of the DSM-IV studies.These revealed shorter rapid eye movement (REM) latencies,

reduced REM sleep, increased delta sleep percentage, reduced aswell as increased number ofsleep spindles (see reference 2, p 643,for review). However, the results were very inconsistent and oftenin conflict with each other.

There are 7 recent studies that focused on sleep architecturedisturbances in ADHD. Two found no significant differences in sleeparchitecture between children with ADHD and controls with DSM-IVreading disorders.41,54 One study found a significantly highernumber ofsleep cycles in ADHD.30 In 3 other recent studies REMsleep was found to be significantly decreased in ADHD children ascompared to normal controls.19,38,44 However, in 1 other studyREM sleep was increased.62 Two studies demonstrated an increasedREM sleep latency.19,38 In contrast, 1 study found an increasedabsolute duration of REM sleep and shorter sleep latencies inADHD.30

REM sleep disturbances have been associated with PLMD28 andinsomnia.(i3 Note that in those studies where disturbances of REMsleep were found, PLMD and REM were not excluded, whereas inthose studies contradicting these findings, these 2 comorbid factorswere indeed excluded. Hence, confounding might have played a rolein the latter studies.

To conclude, many different sleep architecture disturbances havebeen found in ADHD; however no 1 is specifically associated withADHD. Confounding by other sleep disorders might have skewedthe findings of several studies.

Treatment

Specific treatment options for sleep architecture disturbances do not

exist. Although the effect of stimulant use on sleep architecture islargely unknown, 1 recent study revealed that stimulants do not


7/11

affect REM latency or the percentage REM/total sleep.29

Nocturnal Enuresis

Nocturnal enuresis (NE) (Table 1) is, after insomnia, 1 of the mostcommon pediatric sleep-related disorders. It often causes distressand impairment of self-esteem;64 however, it does not result indisturbances ofsleep architecture.65,66

Several studies have addressed the relationship ofADHD and NE.The majority have shown higher rates of NE in children with ADHDas compared with normal controls19,24,26,38,51,67,68 and clinicalcontrols.24 Two studies did not find any relationship.25,50However, in 1 of these studies 28% of the children with ADHD were

using tricyclic antidepressants, which are known to have atherapeutic effect on NE.

The relationship between ADHD and NE seems to be less profoundat higher ages (adolescents).67,68 Furthermore, it has been shownthat although NE generally implies an increased risk forpsychopathology, the increased risk seems to be missing in childrenwith NE and ADHD.69 Both NE70-72 and ADHD73-75 have beenproved to be genetically transmittable. However, 1 study has shownthat the patterns of inheritance of NE and ADHD are independent of

each other.76

To conclude, there is considerable evidence for a link betweenADHD and NE. The conjoined presence does not entail extra risk forother psychopathology. Issues with respect to the prognosis of NEin ADHD are still unresolved.

A limitation of most studies on NE in ADHD is that they failed tomake a distinction between primary and secondary nocturnalenuresis, although these 2 subtypes of NE are distinct in

background, prognosis, and treatment.77 In primary nocturnalenuresis, children have never achieved complete nighttime control,always wetting at least 2 times a month. secondary nocturnalentireties are completely dry at night for a period of at least 6months and then begin wetting again. Secondary enuresis oftenoccurs after personal or familial disturbance (e.g., school problems)and might therefore be found relatively more frequent in ADHD.

Treatment

The usual treatments for NE consists of bladder training, alarmsystems, or pharmacologie agents (tricyclic antidepressants [TCAs],


8/11

desmopressin) and usually have success rates of 70-80%. It isunknown whether these treatment options are as effective in ADHDas in non-ADHD children. Note that TCAs combined with stimulantsmight lead to abnormal heart rhythms and increased bloodpressure. Studies of the effect of stimulants on NE have yielded

very inconsistent results.24,26,29

Excessive Daytime Sleepiness

In children, excessive daytime sleepiness (EDS) (Table 1) may notovertly present as falling asleep during the day or as 'sleepybehavior' such as yawning. In fact, sleepy children may instead

exhibit hyperactivity, inattention, or behavioral problems.18,78 Inchildhood EDS, somnolence may occur only when the child is notengaged in stimulating mental action or lively physical activity. Themultiple sleep latency test (MSLT) measures the ease of fallingasleep over the course of a day in a dark laboratory setting andforms the gold standard in the assessment of daytime sleepiness.One study using an MSLT in 32 boys with ADHD, not treated withstimulants, and 22 matched controls, indicated that the childrenwith ADHD showed a higher physiological tendency to fall asleepduring the day as compared to normal controls.54 A more recentstudy confirmed these findings.62 Furthermore, this studydemonstrated that the sleepiness was not related to the presence ofa sleep disorder such as SDB or PLMD, although children with

concomitant PLMD showed a significantly shorter sleep latency thanthose without PLMD only in the late afternoon. Note that bothstudies showed that EDS in ADHD was not related to poorer sleepquality or quantity.

Subjective measures of EDS (as reported by parents) also showedsignificantly more sleepiness in children with ADHD and/or learningdisorder as compared to normal controls.79

It is yet unknown what mechanisms underlie the suggestedassociation between ADHD and EDS. Usually sleepiness during theday in children is caused by sleep deprivation, sleep fragmentation,and stress of schoolwork.80 However, the above-cited studiesshowed that EDS in ADHD cannot be explained by a reduced sleepquantity or quality or by the presence of concomitant sleep-relateddisorders. One of the theories behind ADHD is that these patientssuffer from a dysregulation of arousal.53-55,62,81 Thisdysregulation has been related to EDS in ADHD.62 Unstable sleeppatterns have been found in ADHDM53,55 and have also beenrelated to arousal dysregulation. Other studies have underlined the

importance of arousal regulation for various cognitive functions andhave linked arousal dysregulation to cognitive dysfunctions in


9/11

ADHD.82,83 The importance of the arousal dysregulation in ADHDis further corroborated by the very beneficial effect ofpsychostimulants.

Weinberg and Brumback have suggested a distinctive disorder fromADHD, primary disorder of vigilance (PDV), which is characterizedby a combined display of the inability to sustain alertness orwakefulness and decreased attention to current activities.84,85They assert PDV can be discerned from ADHD by the presence of acaring, compassionate, affectionate, kind temperament, which isoften absent in ADHD.

Treatment

Psychostimulants are the most effective treatment strategy for EDSas well as for ADHD. Currently, the majority of children diagnosedwith ADHD receive stimulant medication, with rates as high as 85%in the United States.86

Conclusions

Review of the current literature on sleep-related disorders in ADHDled us to draw the following conclusions.

1. There is high evidence that symptoms ofADHD are more likely tobe seen in children with sleep disordered breathing, periodic limbmovement disorder, and insomnia.

2. Symptoms ofsleep disordered breathing (SDB) are reportedmore often by parents of children with ADHD than by parents ofchildren without ADHD. However, there is high evidence that SDB isnot more prevalent in ADHD.

3. Increased nocturnal motor restlessness is more often seen in

ADHD. However, there is only moderate evidence that children withADHD have a higher risk for periodic limb movements or elevatedscores of periodic limb movements as compared to non-ADHDchildren. Restless legs syndrome seems to be related to symptomsofADHD but not to ADHD as a disorder.

4. Insomnia is more often reported among parents of children withADHD than among parents of children without ADHD. Furtherconclusions are hindered due to methodologic limitations.

5. There is high evidence that disturbances ofsleep architecture canbe found in ADHD; however, there is no specific disturbance related


10/11

to ADHD.

6. There is high evidence that nocturnal enuresis is more likely tooccur in children with ADHD than in children without ADHD.

7. There is limited to moderate evidence that children with ADHDshow increased excessive daytime sleepiness.

8. There is limited evidence that children with ADHD are likely toshow unstable sleep patterns.

Clinical Implications

1. SDB, PLMD, RLS, and insomnia may manifest with symptoms of

ADHD. A child presenting with symptoms ofADHD should thereforebe submitted to a rigorous and careful evaluation of potential sleepproblems as part of the clinical history. When sleep-relateddisorders are suspected, subsequent supplementary investigationsmight be carried out.

2. Clinicians working with children with ADHD should be wary ofcomorbid insomnia, particularly when the child is treated withstimulants. Knowing the clinical history is important to determiningpossible predisposing, precipitating, and perpetuating factors.

Additional sleep assessment at home can provide more objectiveinformation about sleep duration and fragmentation. Sleepassessment should last a week to capture possible sleep patterninstabilities. Discrepancies between findings of the interview andsleep assessment should be discussed with the parents and (ifpossible) the child to identify the cause of the discrepancy.

3. Clinicians should be aware of the relationship between ADHD andnocturnal enuresis and of the possible negative psychologicalconsequences of nocturnal enuresis. Asking for miction problems

should be part of the history taking in children with ADHD.

4. Excessive daytime sleepiness can occur covertly in children withADHD and may be displayed only when the child is not engaged in astimulating activity. Daytime sleepiness can be a weighing factor inthe decision whether or not to prescribe stimulants.

Implications for Future Studies

Several methodologic issues may be important for future studies.

First, the majority of the studies discussed are focused oncomparison of group means. Another approach is to compare


11/11

numbers of cases, such as the presence of a particular disorder,between different groups. Such patient-directed approaches yieldadditional clinically important information. However, this approachhas hardly been used in the research on sleep in ADHD. We supporta combined use of both meacutehodologie approaches in order to

reach the highest level of relevant information.

An issue related to this is the absence of consensus criteria onchildhood insomnia. In studies of insomnia in children a patient-directed approach is hampered owing to the lack of consensuscriteria on the diagnosis of insomnia in children. Insomnia criteria inthe present classification systems are still solely focused on theadult population. An effort should be made to establish age-dependent insomnia criteria for children. Such criteria have beenproposed previously;87 however, they have not yet been

implemented.

Third, we found that only a few studies took into account thecomposition of their sample with regard to ADHD subtypes(DSMIV).'' This in spite of the fact that marked differences in sleeponset, nocturnal movements, sleep fragmentation, and efficiencyhave been found between these ADHD subtypes.54,88 Thus,differences in sample composition between studies might contributeto inconsistencies. Ultimately, taking into account ADHD subtypes inresearch might lead to a better prediction of pathogenesis and

treatment effectiveness. Therefore, the exploration of potentiallynew relevant subtypes should be encouraged. A recent attempt hasbeen made by the distinction between "primary (idiopathic) ADHD"and "ADHD secondary to a nocturnal sleep disorder".62

A fourth issue pertains to the wide use of actigraphy as aninstrument to estimate sleep parameters in ADHD. It is generallyconsidered as a reasonably valid and reliable method to measuresleep-wake differences and has a moderate accuracy in estimatingsleep onset and awakening time in normal controls. However,

increased nocturnal motor restlessness in ADHD could affect itsaccuracy in estimating sleep in this population. Therefore, futurestudies should evaluate the concordance of actigraphy andpolysomnography

journal adhd

Documents