Article 9

The Consequences of Insufficient Sleep for AdolescentsLinks Between Sleep and Emotional Regulation

Any review of adolescent lifestyles in our society will reveal more than a dozen forcesconverging to push the sleep/arousal balance away from sleep and toward ever-higherarousal. What harm could there be in trying to push back a little toward valuing sleep? Thepotential benefits, according to Dr. Dahl, seem enormous.

BY RONALD E. DAHL

ADOLESCENTS often “get by” with relatively little sleep,but it may be far less than they need. The observations of manyparents, educators, and clinicians are in close agreement with awealth of scientific data about the growing frequency of thisworrisome pattern of behavior. As discussed in other articles inthis special section, there has been recent progress in under-standing many of the factors that contribute to adolescent sleeploss, including the role of early school starting times and therole of various biological and social influences on adolescents’self-selected bedtimes.

The increasing evidence that teenagers seem to be gettingless sleep leads inevitably to the pragmatic question “Howmuch sleep do adolescents really need?” Unfortunately, themedical/scientific answer to this question seems tautological.Sufficient sleep is defined as “the amount necessary to permitoptimal daytime functioning.”

As impractical as that answer may appear, there are two im-portant reasons for such a definition. First, sleep requirementscan be remarkably different across individuals. Second, at aphysiological level, sleep and waking states are closely inter-twined aspects of a larger system of arousal regulation. (Sleepresearchers often use the Chinese symbol of yin/yang to desig-nate the interrelationship of sleep/wake states.)

At the center of this discussion is a critical and pragmaticpoint: any evaluation of the sleep habits of adolescents must in-clude a careful consideration of the waking consequences ofsleep loss. The question becomes, in essence, “What are thedaytime signs of diminished functioning that indicate insuffi-cient sleep?” While there is a shortage of well-controlled re-

search studies that seek to answer this question, this articlefocuses on the convergence of evidence suggesting thatchanges in mood and motivation are among the most importanteffects of sleep loss. Thus an important place to begin lookingfor evidence of insufficient sleep among adolescents is in thearea of emotional or behavioral difficulties.

Illustration by Brenda Grannan

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Article 9. The Consequences of Insufficient Sleep for Adolescents

There is no shortage of epidemiological and clinical studiesdocumenting recent increases in the rates of many psychiatricdisorders among adolescents. Certainly many complex factorsare likely to have contributed to the emotional and behavioralproblems of teenagers, but the possible link to adolescent sleeppatterns bears some scrutiny. There is clear evidence that sleeploss can lead to the development or exacerbation of behavioraland emotional problems.1 The key question is “How great is thecontribution of sleep deprivation to these problems?” The mag-nitude of this link remains an open question that can only be an-swered through careful empirical research.

In the meantime, these issues have enormous ramificationsfor the fields of medicine and education with regard both to thephysical and mental health of adolescents and to detriments toeffective learning and social development. Many policy deci-sions will be influenced by our understanding and interpretationof the importance of sleep in these areas.

In this article I provide an overview of current scientific andclinical information regarding the consequences of insufficientsleep in adolescents. I pay particular attention to links betweensleep and emotional regulation. The following is a brief outlineof the main points to be presented:

1. Sleepiness. This is the most direct consequence of adoles-cent sleep loss, and it manifests itself most significantly in dif-ficulty getting up on time for school and in falling asleep inschool. These problems can further contribute to conflicts withparents and teachers and to poor self-esteem. Sleepiness is alsoassociated with a strong tendency toward brief mental lapses (ormicrosleeps) that greatly increase the risk of motor vehicle andother kinds of accidents.

2. Tiredness. This is a symptom of sleep loss and includeschanges in motivation—particularly difficulty initiating behav-iors related to long-term or abstract goals and decreased persis-tence in working toward goals.

3. Mood, attention, and behavior. Sleep loss can have nega-tive effects on the control of mood, attention, and behavior. Ir-ritability, moodiness, and low tolerance for frustration are themost frequently described symptoms in sleep-deprived adoles-cents. However, in some situations, sleepy teenagers are morelikely to appear silly, impulsive, or sad.

4. Impact of emotional and behavioral problems. Emotionalarousal and distress can cause both difficulty falling asleep andsleep disruptions. Behavioral problems and family chaos cancontribute to even later bedtimes and to sleep schedules that areever more incompatible with school schedules.

5. Bi-directional effects. There are bi-directional effects be-tween sleep and behavioral/emotional problems. It can be diffi-cult at times to identify the causal links. For example, adepressed adolescent with severe sleep problems may beshowing sleep disturbances that stem from depression or moodproblems that stem from sleep disruption. Sleep loss can alsocontribute to a negative spiral or vicious cycle of deterioration.That is, sleep loss can have a negative effect on mood and be-havior, which leads to subsequent emotional/behavioral diffi-culties that further interfere with sleep. This produces asequence of negative effects in both domains. In some clinical

cases, such negative spirals appear to be a pathway to with-drawal from school or serious psychiatric problems.

The Need for Sleep: An Overview

Before discussing the specific consequences of insufficientsleep in adolescents, it is necessary to begin with a general over-view on what sleep is and why it is necessary at all.

Sleep is not simply rest. Mere rest does not create the restor-ative state of having slept. (Anyone who doubts this should trythe following experiment tonight: spend eight hours resting inbed, with eyes closed, body relaxed, mind floating, in a deeplytranquil state, but without ever going to sleep; then keep trackof your mood and performance tomorrow.) The fundamentaldifference between sleep and a deeply relaxed wakefulness isthat sleep involves dropping into a state with a relative loss ofawareness of and responsiveness to the external world. Thisstate of unresponsiveness appears to be necessary for the restor-ative processes that occur during sleep to take place.

Furthermore, sleep itself is an active process. Sleep involvesdynamically changing patterns and progressive stages, withsome brain regions showing a great deal of activity in somesleep stages. Moreover, there are several aspects of sleep neces-sary for full restoration, including the continuity, timing, andpatterning of different stages of sleep, as well as the timing ofthe sleep in relation to other biological rhythms.

For example, if subjects are permitted a full night’s sleep butare awakened every 15 minutes for brief periods, on the fol-lowing day they will report tiredness, fatigue, and emotionalchanges similar to having obtained insufficient amounts ofsleep. Similarly, if subjects are permitted as much sleep as theyneed but are selectively deprived of one sleep stage—such asREM (rapid eye movement) sleep or delta sleep—they also re-port daytime consequences. And, as anyone who has experi-enced jet lag can attest, sleep that occurs at the wrong circadianphase is often fragmented and inefficient at restoration.

Sleep is not some biological luxury. Sleep is essential forbasic survival, occurring in every species of living creature thathas ever been studied. Animals deprived of sleep die. (Experi-ments with rats show that they can survive without sleep forabout as long as they can survive without food.) Yet the specificfunction of sleep—why it is necessary for survival—remains ascientific mystery and the focus of a great deal of investigation.

Within this scientific mystery, however, are two importantclues that are relevant to discussions of sleep and adolescenthealth. First, sleep seems to be particularly important during pe-riods of brain maturation. (Across species, maturing individualssleep more than fully mature individuals.) Second, sleep is nat-urally restricted to times and places that feel safe. Most specieshave evolved mechanisms to ensure that sleep is limited to suchsafe places as burrows and nests and to times of relative safetyfrom predators. In humans, there is a similar tendency for safefeelings to promote sleep while feelings of threat or stress tendto inhibit sleep.

These links between sleep and stress are an important sourceof sleep disruption among adolescents. A key point can be best

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illustrated by a brief consideration of the evolutionary under-pinnings of these biological links between sleep and emotion.For most of early human history, large nocturnal-hunting carni-vores surrounded our ancestors, who had no access to physi-cally safe sleep sites. (Humans cannot sleep in trees or on cliffedges, because we lose all muscle tone during REM sleep.) Inthe human ancestral environment, the main protection againstpredators was a close-knit social group. The human brainevolved under conditions that made this sense of social be-longing and social connectedness the basis for feelings of rela-tive safety. Natural tendencies in the human brain continue toreflect these links, so that fears of social rejection can evokepowerful feelings of threat and so lead to sleep disruption, whilefeelings of love, caring, and social connection create a feelingof safety and so promote sleep.

Finally, it is important to consider the ways in which thesleep and vigilance systems change during adolescent develop-ment. The maturation of humans during puberty includes phys-ical and mental changes in preparation for taking on adult roles(with increased demands for threat appraisal and response).Changes in the vigilance system include a greater capacity forsleep disruptions from social stresses, including fears, anxieties,and emotional arousal.2 Thus adolescent sleep systems appearto become more vulnerable to stress at a time when social tur-moil and difficulties are often increasing.

Consequences of Insufficient Sleep in Adolescents

There is a surprising lack of controlled studies examining theeffects of sleep deprivation or insufficient sleep among adoles-cents. However, there is extensive circumstantial evidence,clinical evidence, and research in adults that is relevant to thesequestions. While there is a general convergence of these find-ings, one important caveat is that we need a greater number ofdirect investigations. A second note of caution is that we lackinformation about long-term or chronic effects of insufficientsleep, since the limited data available have addressed only theimmediate and short-term effects of sleep loss.

In brief, there are four main effects of acute sleep loss: 1)sleepiness, 2) motivational aspects of tiredness, 3) emotionalchanges, and 4) alterations in attention and performance. Beforediscussing each of these briefly, I wish to stress one generalprinciple that applies across categories: the influence of effort.That is, the effects of sleep deprivation can be offset or evenoverridden for short periods of time by increased effort (or byincreasing the external motivation to perform through rewardsor punishments). The good news here is that most capabilitiescan be maintained over a short interval if necessary, while thebad news is that everything is harder to do. In some ways this isthe cardinal feature of sleep deprivation: it takes increased ef-fort to perform the same cognitive, emotional, or physical tasks.

1. Sleepiness. The most obvious and direct effect of inade-quate sleep is a feeling of sleepiness. Sleepiness is most prob-lematic during periods of low stimulation, such as in theclassroom, when reading or driving, or when doing repetitive

activities. Highly stimulating activities—particularly those in-volving physical activity or emotional arousal—can often maskmoderate levels of sleepiness. Thus many sleep- deprived ado-lescents report that they can stay out very late at night and notfeel tired, whereas if they were to lie quietly reading a book,they would fall asleep in minutes.

Another important aspect of sleepiness is the tendency to-ward brief mental lapses or micro-sleeps. Often, an individualis not even aware of these short gaps in awareness and respon-siveness. However, such a lapse in the midst of driving, oper-ating machinery, or doing anything else that requires vigilancecan have dire consequences.

Several indirect consequences of sleepiness are also worthmentioning. These include adolescent conflicts with parentsand teachers that arise from the difficulty of getting up in themorning or the ease of falling asleep in class; increased use ofstimulants (particularly caffeine and nicotine); and synergisticeffects with alcohol (the impairments from a combination of al-cohol and sleepiness appear to be more than additive, resultingin a deadly combination of influences).

2. Tiredness. A separate symptom of sleep loss that can bedefined as a feeling of fatigue or decreased motivation is tired-ness. Tiredness makes it difficult to initiate (and persist at) cer-tain types of behavior (especially tasks deemed boring ortedious). The effects of tiredness are less apparent when per-forming tasks that are naturally engaging, exciting, or threat-ening—perhaps because it is easier to recruit extra effort tooffset tiredness. Conversely, the effects of tiredness are morepronounced for tasks that require motivation to be derived fromabstract goals or consequences (e.g., reading or studying unin-teresting material in order to increase the chances of attainingsome future reward).

Tedious tasks without the imminent prospect of reward (orfear of immediate consequences) are much more difficult to ini-tiate and complete when one has been deprived of sleep. Simi-larly, tasks that require planning, strategy, or a complexsequence of steps to complete are more difficult when one istired. This general category of tasks (requiring motivationlinked to abstract goals, delayed rewards/consequences, plan-ning, strategy, and so on) involves abstract processing areas inthe front of the brain (regions of the prefrontal cortex) that ap-pear to be particularly sensitive to sleep deprivation.3 The po-tential relevance of these types of motivational changes toeducational goals and processes seems obvious.

3. Emotional changes. The emotional changes that are sec-ondary effects of sleep loss are very important but very com-plex. There are at least three factors that make this acomplicated area for investigators: 1) the emotional effects ofsleep deprivation appear to be highly variable across individ-uals and across situations, 2) emotion and emotional regulationare very hard to measure accurately, and 3) there are bi-direc-tional interactions between mood and sleep disturbances (thisthird aspect was noted above and will be addressed separatelybelow).

One of the main sources of information in this area comesfrom clinical descriptions of children and adolescents with var-ious sorts of sleep disorders or transient sleep disruptions. There

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Article 9. The Consequences of Insufficient Sleep for Adolescents

are also a few studies (including ongoing research in our labo-ratory) that obtain measures of emotion before, during, and aftera single night of sleep deprivation, and then again following arecovery sleep.

The major theme across these studies is evidence suggestingmood lability. Not only does there appear to be greater vari-ability in emotional states following sleep loss, but there alsoappears to be less control over emotional responses in many ad-olescents. For example, if faced with a frustrating task, a sleep-deprived teenager is more likely to become angry or aggressive.Yet, in response to something humorous, the same subjectmight act more silly or inane. Several adolescents reported in-creased crying reactions during sad scenes in videotapedmovies when they were sleep-deprived. Many subjects reportedincreased irritability, impatience, and low tolerance for frustra-tion when asked to perform tedious computer tasks. In general,these findings often looked like a decrease in inhibition or con-scious control over emotions following sleep loss. It is also im-portant to point out that some subjects seemed to show nomeasurable changes in any emotion when sleep-deprived.

These results are quite preliminary, include a high degree ofvariability across individuals, and will require replication withlarger samples to establish statistical significance. However,these findings fit very well within a general pattern of similarobservations regarding effortful control. That is, the primaryemotional changes following sleep loss suggest a decrease inthe ability to control, inhibit, or modify emotional responses tobring them into line with long-term goals, social rules, or otherlearned principles. Effortful control over emotion involves re-gions of the prefrontal cortex of the brain that are similar tothose discussed previously with regard to abstract goals.

Changes in emotional regulation that result in decreased con-trol following sleep loss could have serious consequences interms of many high-risk behaviors among adolescents. The in-ability to control emotional responses could influence aggres-sion, sexual behavior, the use of alcohol and drugs, and riskydriving. Clearly, additional research will be needed to better de-lineate these complex but important issues relevant to adoles-cent health.

4. Changes in attention and performance. Following sleeploss, changes in attention and performance also represent acomplex area of investigation in children and adolescents.There are three main points. First, sleep loss is associated withbrief mental lapses in attention during simple tasks that can bepartially offset by increased effort or motivation. Second, sleepdeprivation can sometimes mimic or exacerbate symptoms ofADHD (attention deficit/hyperactivity disorder), including dis-tractibility, impulsivity, and difficulty with effortful control ofattention. Third, there is also emerging evidence that sleep dep-rivation has marked influences on the ability to perform com-plex tasks or tasks that require attention in two or more areas atthe same time.

While the first point about brief mental lapses has alreadybeen addressed, the latter two points warrant some discussion.A potential link between ADHD symptoms and sleep depriva-tion has received considerable discussion from several investi-gators.4 Both ADHD and sleep deprivation are associated with

difficulty with self-control of behavior, attention, and impulses.Both ADHD and the daytime symptoms of sleep deprivationwill often respond to stimulant medication. Furthermore,ADHD symptoms are more frequent in children with sleep dis-orders, and there has been some reported improvement inADHD symptoms in children following treatment of sleepproblems. Finally, other studies have reported increased rates ofsleep complaints and disorders in children diagnosed withADHD. This is a very complex area, and disentangling the con-nections and relative contributions across these domains will re-quire additional careful studies.

One pragmatic recommendation, however, is quite simple.For any child or adolescent who exhibits symptoms of ADHD,the importance of a good night’s sleep and a regular sleep/wakeschedule should be emphasized to avoid the consequences ofsleep loss that could exacerbate symptoms.

One of the most interesting areas of study is evidence thatsome types of complex tasks may be particularly sensitive to theeffects of sleep deprivation. James Horne has presented exten-sive evidence showing that dual tasks and tasks that require cre-ative or flexible thinking are sensitive to sleep loss.5 (Thesetasks all require abstract processing in areas of the prefrontalcortex.) Our own research group has generated similar findingsin its examination of dual tasks following sleep deprivation inadolescents and young adults. For example, students with onenight of sleep deprivation exhibited no significant changes inperformance on a difficult computer task and showed no effecton postural balance. However, when the students performedboth tasks simultaneously, sleep deprivation had a marked ef-fect on balance.6 In recent pilot studies we have also found thesame pattern of results in adolescents performing cognitive andemotional tasks. Performance at either task could be maintainedfollowing sleep deprivation—but not both.

On one hand, detriments in performing a dual task (like con-trolling thoughts and feelings at the same time) might sound likean esoteric or subtle effect of sleep deprivation; on the otherhand, it is important to point out that fluency in such dual tasksis the foundation of social competence. These are the daily chal-lenges that must be balanced in the everyday life of adolescents:thinking and solving problems while navigating the emotionalreactions of complex social situations, using self-control overimpulses and emotions while pursuing goals, experiencinganger yet weighing the long-term consequences of actions. Iffurther research substantiates the marked effects of insufficientsleep on these types of complex tasks in adolescents, then weshould have significant concerns about the importance of sleeppatterns in the normal development of social competence.

Sleep and Emotional Disorders in Adolescents

It is essential to underscore the complex intersection betweensleep regulation and behavioral and emotional problems in ad-olescents. Clearly, there are two-way interactions between thesesystems. The regulation and timing of sleep can be altered by

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behavioral or emotional disorders, while cognitive, behavioral,and emotional control during daytime hours can be influencedby the way adolescents sleep. Furthermore, daytime activities,changes in the environment, and stressful events can have pro-found transient effects on sleeping patterns in the absence ofany clear-cut psychopathology. In addition, medications used totreat psychiatric disorders often affect sleep, and sleep loss canexacerbate mood and behavioral symptoms.

Perhaps the best-studied example of such interactions is therelationship between sleep and depression. Subjective sleepcomplaints are very common in children and adolescents whohave been diagnosed with Major Depressive Disorder (MDD).Symptoms include insomnia (75% of cases) and hypersomnia(25%). Hypersomnia difficulties are reported more frequentlyafter puberty. Insomnia symptoms usually include difficultyfalling asleep and a subjective sense of not having slept deeplyall night.

Recently, clinicians and researchers have seen increasingnumbers of adolescents with overlapping phase delay disordersor other sleep/wake schedule disorders associated with depres-sion. Depressed adolescents frequently have difficulty fallingasleep, are unable to get up or refuse to go to school, sleep untillate in the day, complain of extreme daytime fatigue, and, overtime, shift to increasingly more delayed sleep/wake schedules.Likewise, surveys reveal that adolescents who get less than6¾ hours of sleep each school night or report more than a two-hour difference between school night and weekend bedtimeshave a higher level of complaints of depressed mood than ado-lescents who get more sleep or who sleep on more regular sleep/wake schedules.

Clinicians who are experienced with these problems havepointed out that in many cases it is difficult to differentiate de-creased motivation, school refusal/anxiety, delayed circadianphase, attention difficulties, and depressive symptomatology.Clearly, both sleep patterns and behavioral symptoms must becarefully assessed in an effort to prevent the problems, diagnosethem accurately, and plan successful treatment.

There is also evidence of changes in the sleeping electroen-cephalograms (EEGs) of depressed adolescents, including in-creased time to fall asleep and altered patterns of REM sleep.Furthermore, changes in EEG measures of sleep predicted anincreased recurrence of depressive episodes during longitudinalfollow-ups in early adulthood.7

In some cases, treatment of sleep complaints and prob-lems—including regularizing the sleep/wake schedule, cogni-tive behavioral therapy for insomnia, and short-term treatmentwith medication for severe insomnia—can have a positive im-pact on depressive symptoms.8 On the other hand, effectivetreatment of depression can also be a critical aspect of im-proving sleep.

Negative Spirals?

As I described above, one area of concern with regard to theinterconnections between sleep and emotional disturbances is

the potential for a progressive sequence or spiral of negative ef-fects. Insufficient sleep can amplify emotional difficulties,which can then produce further sources of distress and in-creased disruption of sleep. The reason for this concern arisesmore from clinical experience than from any controlled studies,and so the concern is perhaps best illustrated by describing acase.

Jay had a history of poor sleep habits (e.g., bedtimes pastmidnight, erratic sleep/wake schedule) beginning in about sev-enth grade. In ninth grade the problems became worse as hestruggled to get to sleep at night (usually falling asleep at 1 a.m.)and to wake up in the morning and then had problems with dis-tractibility and behavior at school. He also reported some symp-toms of depression, including loss of interest in some activities,daytime fatigue, and worsening performance at school. Hissymptoms improved transiently in the summer, when he sleptfrom 3 a.m. until noon.

In 10th grade Jay began attending a high school that startedat 7:30 a.m., which required him to wake up at 6 a.m. to meetthe school bus at 6:30 a.m. He had a very difficult time gettingup for school at that hour because his average bedtime was 2a.m. He made several attempts to go to bed earlier but foundhimself unable to fall asleep. He was never able to followthrough in a way that would permit him to establish an earlierpattern of bedtime, and he quickly reverted to his 3 a.m.-to-noon sleep schedule on all weekends and holidays. Jay some-times stayed up working at his computer or watching televi-sion—he says this was because he hated the feeling of lying inbed trying unsuccessfully to fall asleep. Before long, he wasregularly missing school or arriving late and falling asleep inclass.

Jay, who had at one time been identified as a gifted student,was failing most of his classes and appeared increasingly le-thargic, subdued, and uninterested in school. His school coun-selor referred him to a mental health clinic. Over the course ofseveral months, he was diagnosed as having depression withsome ADHD symptoms (e.g., difficulty finishing tasks, dis-tractibility). Trials of antidepressants and stimulant medica-tion resulted in small transient improvements in somesymptoms, but Jay was never able to reestablish good sleeppatterns that were compatible with his school schedule. Even-tually he withdrew from school, became increasingly de-pressed and withdrawn, and was hospitalized after a serioussuicide attempt.

At the time of hospitalization, Jay had severe chronic in-somnia and a major depressive disorder. Despite multiple inter-ventions, these problems persisted. He showed very littlemotivation to return to school and appeared to have chronic de-pressive symptoms. At discharge his long-term prognosis wasnot promising.

In a case such as Jay’s, it is impossible to disentangle the rel-ative contributions of the sleep and mood dysregulations. Whileno general conclusions can be drawn from this single case, itdoes illustrate the complexity of these interactions and the im-portance of obtaining a better understanding in these areas.

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Article 9. The Consequences of Insufficient Sleep for Adolescents

Policy Decisions for Today and Direction for the Future

Frequently in this article I have cautioned readers about theneed for additional research to improve our understanding ofthe complex issues arising from the consequences of insuffi-cient sleep among adolescents. Our current knowledge is pre-liminary and based on a paucity of controlled data.Furthermore, we are probably at an equally early stage in ourunderstanding of the behavioral and emotional problems of ad-olescents.

Nonetheless, behavioral and emotional difficulties are cur-rently the largest source of morbidity and mortality among ad-olescents. While it is possible that sleep loss makes only aminuscule contribution to adolescents’ problems with emo-tional regulation, it is extremely likely that it plays some role. Itis also quite possible that insufficient sleep plays a significantrole in leading up to some of these problems in a vulnerable setof individuals.

Identifying vulnerability to sleep loss may represent an im-portant future direction for research, since there appear to besuch large individual differences in the effects of acute sleeploss. Such vulnerability could be related to a tendency to needmore sleep, to being a “night owl,” or to a biological vulnera-bility toward emotional disorders.

Clearly, more research is needed to help inform policymakers, whose decisions will further affect adolescent sleeppatterns. Cost-benefit analyses regarding the relative impor-tance of sleep will require more precise quantification in theseareas. In the meantime, one might make a reasonable case thatthe odds are heavily in favor of sleep as an increasingly impor-tant health concern among adolescents.

To reiterate the main point with which I began, adequatesleep is defined as the amount necessary for optimal daytime

functioning. It appears that the potentially fragile underpinningsof adolescent social competence (controlling thoughts and feel-ings at the same time) may be most sensitive to the effects of in-adequate sleep. Any review of adolescent lifestyles in oursociety will reveal more than a dozen forces converging to pushthe sleep/arousal balance away from sleep and toward ever-higher arousal. What harm could there be in trying to push backa little toward valuing sleep? The potential benefits seem enor-mous.

Notes1. Ronald E. Dahl, “The Regulation of Sleep and Arousal: Devel-opment and Psychopathology,” Development and Psychopatholo-gy, vol. 8, 1996, pp. 3-27.2. Ronald E. Dahl et al., “Sleep Onset Abnormalities in Depressed Adolescents,” Biological Psychiatry, vol. 39, 1996, pp. 400-410.3. James A. Horne, “Human Sleep, Sleep Loss, and Behaviour Im-plications for the Prefrontal Cortex and Psychiatric Disorder,” Brit-ish Journal of Psychiatry, vol. 162, 1993, pp. 413-19.4. Ronald D. Chervin et al., “Symptoms of Sleep Disorders, Inat-tention, and Hyperactivity in Children,” Sleep, vol. 20, 1997, pp. 1185-92.5. Horne, op. cit.6. Abigail Schlesinger, Mark S. Redfern, Ronald E. Dahl, and J. Richard Jennings, “Postural Control, Attention and Sleep Depriva-tion,” Neuroreport, vol. 9, 1998, pp. 49-52.7. Uma Rao et al., “The Relationship Between Longitudinal Clini-cal Course and Sleep and Cortisol Changes in Adolescent Depres-sion,” Biological Psychiatry, vol. 40, 1996, pp. 474-84.8. Ronald E. Dahl, “Child and Adolescent Sleep Disorders,” in idem, ed., Child and Adolescent Psychiatric Clinics of North Amer-ica: Sleep Disorder (Philadelphia: W. B. Saunders, 1996).

RONALD E. DAHL, M.D., is an associate professor of psychiatry andpediatrics at the University of Pittsburgh Medical Center, Pittsburgh,Pa.

From Phi Delta Kappan, January 1999, pp. 354-359. © 1999 by Phi Delta Kappan. Reprinted by permission.

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