Les adolescents présentent souvent des symptômes de somnolence et de lassitude. Jusqu’à 40 % des adolescents en santé ressentent une somnolence régulière, définie comme une augmentation de la tendance à s’endormir. La lassitude est la perception de manque d’énergie après des activités normales, dont jusqu’à 30 % des adolescents en santé font état. Le syndrome de fatigue chronique est un syndrome inhabituel qui s’accompagne d’intense lassitude et d’autres symptômes physiques et neurologiques. Tous les adolescents qui ressentent de la somnolence et de la lassitude doivent subir une évaluation approfondie, mais le médecin trouve rarement un trouble médical sous-jacent et traitable. Dans la plupart des cas, la lassitude et la somnolence chez les adolescents sont attribuables au mode de vie et, notamment, au manque de temps consacré au sommeil. Les médecins sont bien placés pour dépister, évaluer et prendre en charge ces problèmes courants chez les adolescents.

The goals of the present paper are to review the available literature on the complaint of ‘being tired’, particularly focusing on the common symptoms of sleepiness and fatigue, and to suggest an approach to assessing and managing this troublesome and sometimes disabling symptom.

The tired teen may report fatigue or sleepiness, or often both. For example, a 14-year-old boy may report that he feels too tired to go to school every day (fatigue), but that he is no more likely to fall asleep during the day than his peers (not sleepy). Alternatively, a 16-year-old girl may report that she repeatedly falls asleep in class (sleepiness), yet she has the energy to do a wide array of school, sport and social activities (not fatigued). In reality, the tired teen often has an overlap of these common symptoms, yet it is important for the teen to be clear about what he or she is experiencing because it aids the clinician in the management of the condition. Therefore, although somewhat artificial, for the purposes of defining and discussing a differential diagnosis, a separation of sleepiness and fatigue may be useful.

Not surprisingly, the usual cause of excess sleepiness is insufficient or inadequate sleep – both very common during the teen years. A recent publication of the American Academy of Pediatrics’ Working Group on Sleepiness in Adolescents/Young Adults (1) summarized that teens need 9 h to 10 h of sleep per night for optimal functioning, but for a variety of reasons, many do not get this. Lifestyle factors contributing to this problem include early start times for most high schools, and an increasing amount of extracurricular and employment demands on many adolescents. The availability of highly entertaining computer and video games, as well as late night socializing via the Internet also contribute to the unwillingness to get to bed at a decent time to get the recommended 9 h to 10 h of sleep. Such teens may find napping in the afternoon unavoidable, giving them an ill-timed sense of energy late in the day, further contributing to the late nights. Teenagers with insufficient sleep typically catch up on sleep on weekends, with very late rise times on weekend mornings.

Although unusual, sleep disorders must be ruled out in the sleepy teen. Delayed sleep phase syndrome (DSPS) is the most common sleep disorder in adolescents, with an incidence as high as 7% in some studies (1). Teens with DSPS have difficulty falling asleep when they go to bed as a result of a circadian rhythm disorder, in which their internal sleep-wake cycle is not synchronous with the world around them. They complain of an inability to fall asleep when they go to bed, as opposed to teens who choose to stay up late but fall asleep very quickly once they are in bed. Sleep-disordered breathing (obstructive sleep apnea) can also result in daytime sleepiness in teens, and is often related to enlarged tonsils and adenoids or obesity. Typically there is a history of snoring. Uncommon sleep disorders, such as narcolepsy, periodic leg movement during sleep and restless leg syndrome can be considered when daytime sleepiness is severe and chronic. There are often specific complaints to suggest these disorders, such as a history of sudden sleep attacks or a restless uncomfortable feeling in the legs only resolved by movement.

Regardless of the cause, the consequences of excessive sleepiness in teens can be serious; clear associations have been made with many adverse outcomes, including poor school performance, mood disturbance and increased risk of accidents, particularly motor vehicle crashes (1,2,8).

The differential diagnosis of fatigue is extensive, and multiple causes frequently coexist. Almost every known illness has the potential to affect one’s energy level and sleep patterns; therefore, listing possible causes of fatigue would be encyclopedic. For this reason, the discussion of fatigue requires the caveat that the symptom is not readily explainable by a diagnosed physical or psychiatric illness (especially anxiety and depression). In some adolescents, fatigue is one of several medically unexplained symptoms that should prompt the physician to consider a somatization disorder (21).

CFS is often used to describe a constellation of symptoms of which the predominant symptom is severe fatigue. The syndrome often appears to be triggered by an illness, but evolves into a chronic state of poor functioning that is related to poor physical conditioning, sleep disturbance and is often perpetuated by psychological factors. Although numerous causes have been suggested, the etiology of CFS remains unknown. Infectious, immune and neurological causes have been studied, yet a clear etiology remains lacking. Observations that some patients with CFS also experience postural tachycardia and orthostatic intolerance (22) have led to questions about whether autonomic nervous system dysfunctions may be etiologically related to CFS; however, this hypothesis remains controversial (23). The most commonly encountered physical symptoms are malaise, headache, sore throat, sleep disturbance, memory and concentration impairment, nausea, joint and abdominal pain (13,16,19,24). Significant functional impairment is part of the presentation, as are worsening symptoms with physical or mental exertion. Diagnostic criteria for children and teens with CFS remain controversial, and many physicians feel that the CFS label should be avoided for children and teens because it may erroneously imply an unremitting condition with a lifetime of functional impairment (16,17).

Taking a medical history from the tired teen is the most important diagnostic intervention. At least part of the history must be taken with the teen alone to ensure that accurate information is obtained about topics such as substance use, school attendance and mental health. A detailed history provides reassurance that a thorough approach has discovered or ruled out any pernicious conditions. Integrating holistic questioning from the beginning of the interview gives the teen and the family the idea that investigation of psychosocial stressors is just as important as questions about their physical health. To delay this line of questioning until after the physical examination and laboratory investigations delivers the message that psychosocial inquiries are only relevant in the absence of physical causes.

Open-ended questions are extremely helpful in understanding the onset and course of the symptoms, and the teen should be encouraged to tell the story of their illness. This often reveals a specific trigger for the onset of sleep disturbance or fatigue – such as a concomitant illness, notably a viral illness, or a significant life event, such as a death in the family, travel over time zones or a change in daily routine. The duration and stability of the complaint may give clues to psychosocial or environmental contributors, such as persistence of symptoms during weekends and holidays, and in different seasons. Many teens have tried prescription and nonprescription remedies for their symptoms, and inquiries should be made about the use of herbal and alternative therapies.

To determine whether the teen has predominately fatigue or sleepiness, a detailed sleep history is essential. A recently published screening tool, referred to by the acronym BEARS (25), can help to structure the history (Table 1).

TABLE 1 Screening questions for sleep difficulties in adolescents

A detailed review of symptoms is needed to facilitate which investigations are needed and also to ascertain whether other somatic symptoms are present. Inquiry should be made into constitutional symptoms such as fever, appetite and weight changes. The review should be systematic and specific, because many teens do not volunteer what may seem to them to be an unrelated symptom. For example, a 13-year-old girl may be experiencing heavy menstrual bleeding, but she may not think to share this with the doctor unless specifically prompted. Many teens with complaints of chronic tired feelings also report frequent pain symptoms (head, back and abdomen) in addition to vague complaints such as dizziness, weakness, and poor concentration and memory (13,16,19,23).

When assessing the psychosocial well-being of the teen, the commonly used HEADSS interview remains useful. Please refer to the commentary by Grant (pages 15–18) published in this Journal and the Sacks and Westwood article (26) outlining the use of this interview. The clinician can focus on the symptom’s impact on the teen’s ability to meet age-appropriate expectations, particularly looking at missed school or shifts at work, and changes in social activities. It is very helpful to ask the teen to give examples of the symptom from the past week, such as ‘How has being tired affected you this week? Was there anything you could not do?’ When teens have missed out on their usual activities, what is filling their time? If they are not going to school, are they watching television or spending time on the Internet? Finding out who is at home during the day if the teen is missing school can give some clues to family dynamics. A detailed screening for mood and anxiety disorders is one of the most important parts of the interview of the tired teen. The HEADSS interview also allows the clinician to understand the competing demands in the teen’s life in terms of overscheduling.

Finally, the teen’s prior illnesses and medical history may direct the physical examination and investigations toward a specific diagnosis, but may also reveal a pattern of prolonged illnesses and somatic complaints. Many teens with persistent symptoms report significant impairment with illnesses or events that are not typically associated with prolonged absenteeism, such as the teen who missed three weeks of school following their wisdom teeth extraction or the teen who is routinely home for a week with cold symptoms. The family history may reveal similar patterns of illness behaviour, with a parent themselves experiencing persistent fatigue or chronic pain.

Unless the history provides a specific organ system to focus on, the physical examination in the tired teen needs to be thorough and general, with attention paid to ruling out any chronic or infectious illnesses (9,16). Before the examination, the physician should already have a good sense of the patient’s level of functioning, communication and affect. Observing the teen’s personal hygiene, their choice of clothing and their ability to make eye contact with the doctor is helpful. Does the teen look tired during the interview, with persistent yawning and a sense of indifference to the questions? What is the interaction between the teen and the parent when they are together? Is the teen able to speak when the parent is present, or is he or she silenced?

Vital signs should include temperature and orthostatic measurements. A height and weight measurement should be taken. Growth parameters should be plotted and compared with prior measurements when available. The head and neck examination should include palpation over the sinuses, and assessment of cranial nerves and fundoscopy. The chest should be examined for evidence of heart or respiratory illness, and the abdomen should be evaluated for the presence of hepatosplenomegaly or pelvic masses. Unless the history suggests possible pregnancy or pelvic pathology, an internal examination is not usually necessary. Lymphadenopathy should be looked for. The skin should be examined for rashes, pallor or hyperpigmentation, and the extremities for any evidence of arthritis. The neurological examination needs to include an assessment of muscular strength and gait.

Laboratory testing should be directed by findings on the history and physical examinations; certain tests are indicated for most teens complaining of being tired, and to eliminate those conditions that are vague and do not always present with specific symptoms (9,16). Suggested baseline testing includes a complete blood count with differential and platelet counts, erythrocyte sedimentation rate, fasting glucose, electrolyte, urea, creatinine, liver function tests, albumin, creatine kinase, mononucleosis screen, thyroid stimulating hormone, thyroxin, pregnancy test and urinalysis. The results of the history, physical examination and the baseline tests may suggest other investigations, such as rheumatologic tests (eg, antinuclear antigen, rheumatoid factor, complement or immunoglobulin tests), a search for an occult infection (eg, sinusitis, HIV or Lyme disease) or an endocrinological illness (eg, Addison’s disease). In circumstances in which the cause of the sleepiness is clear (eg, not sleeping enough), laboratory investigations can be deferred pending response to initial interventions. The variety of accompanying somatic symptoms, and the duration of the fatigue and sleepiness can lead to overinvestigation and repeating previously normal blood work. It is important to limit this as much as possible because it can delay the teen and their family’s ability to move toward getting better.

Following completion of the history, physical examination and laboratory investigations, the clinician’s primary focus becomes providing feedback to the patient and family, and proceeding with treating underlying causes and managing the symptoms, with a focus on having the teen return to normal functioning as soon as possible. Treatment of any conditions identified on testing is necessary, but it is important to not use the discovery of a minor condition as the sole explanation of the teen’s symptoms. For example, an adolescent girl with mild iron deficiency anemia will likely benefit from iron therapy; however, the clinician should still council about the importance of sleep hygiene and regular exercise to maintain normal energy levels throughout the day.

For the teen with sleepiness of which the obvious cause is insufficient sleep, the clinician can assist the teen by discussing what is known about good sleeping habits. Table 2 lists common advice given to the overtired teen.

TABLE 2 Guidance for teens getting too little sleep

Parents should be aware of the guidance that teens are receiving about sleep hygiene, although they should not be in charge of it. Many sleep-deficient teens have sleep-deficient parents who may themselves benefit from hearing the sleep counselling information provided to the teen. Parents can be reminded that a teen’s late night habits may represent a need for increased privacy and time alone –something that is hard to achieve in a busy household. Parents can be asked to consider whether their teen is over-scheduled, thus not leaving enough time for homework, socializing, fun and ‘downtime’ during normal waking hours.

For most teens with poor sleep hygiene and those with mild DSPS, the above advice to teens and families may be adequate to resolve the daytime tiredness. For those with more severe and prolonged DSPS, a more intensive program of sleep rehabilitation may be needed. Review articles (27,28) detailing the management of paediatric sleep disorders have been published, and if available, referral to a sleep specialist may be helpful.

Management of the teen with unexplained fatigued can be very challenging (9,16,29). Whether the teen has isolated chronic fatigue or the more encompassing CFS, starting with providing very clear feedback to the teen and their family is critical. Even for teens with mild fatigue of a short duration, this approach can be used early, perhaps avoiding deterioration into a more pervasive condition (Table 3).

TABLE 3 Suggested feedback to teens and families regarding chronic fatigue

Before discussing specific interventions, the physician should ensure that the teen and their family are ‘on board’ with proceeding to the management phase. The importance of this step in managing fatigued teens cannot be overstated because the recommendations that the doctor makes are unlikely to be followed unless the family and the teen are prepared to move on (16). Lingering doubts about the completeness of the testing may not allow the parent and the teen to push through the rehabilitation, which may be challenging. Helping the family to understand possible psychological contributors is important, but it needs to be handled cautiously. An explanation that some children with chronic symptoms have a tendency to ‘internalize’ their feelings may help the family understand the reasons for further psychological evaluation, even though the child may not express any worry or unhappiness. There is evidence that teens with parents who do not endorse psychological contributors to chronic fatigue have a poorer prognosis than other fatigued teens (30). It is also important to warn teens and families ahead of time that the management may seem ‘backwards’ to them. Families may be expecting physicians to help with the symptoms and then function can return, whereas physicians propose a return to function followed (hopefully) by a reduction of symptoms (Table 4).

TABLE 4 An approach to managing the fatigued teen

Most outcome studies (11,23,29,31–33) suggest that at least 50% of teens with chronic fatigue and CFS have significant improvement in symptoms and daily functioning, although recovery is often delayed several years. More severe illnesses with more functional impairment suggest a poorer long-term prognosis (11).

The tired teen is commonly encountered by clinicians who work with adolescents and their families. Our approach to helping patients must begin with ruling out physical and psychiatric conditions, then moving to assist the teen with lifestyle and rehabilitation to return to a normal level of functioning. Throughout this process, a therapeutic relationship should be established and maintained with the teens and their families if they are to follow recommendations for changes to established routines. Most teens with these conditions are expected to recover, although there is a subset of teens with CFS in whom prognosis is guarded and long-term management may be necessary.

The author would like to thank the members of the Adolescent Health Committee for their assistance with editing the present paper.