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The Sleepy
Teenager
Kyle P. Johnson , M.D.
(This article was first printed in the November
2001 issue of the Harvard Mental Health Letter.
For more information or to order, please go
to http://health.harvard.edu/mental.)
The rapid physiological, emotional, and social
changes of adolescence often have disturbing
effects on sleep. Teenagers need more sleep than
school age children but usually get less, and
the shortfall causes many problems. Daytime fatigue
and drowsiness may affect schoolwork by reducing
concentration and short-term memory. Sleepy teenagers
are more easily injured, especially in traffic
accidents, and lack of sleep raises the risk
of depression and the use of alcohol and illicit
drugs.
A standard way to measure daytime drowsiness
is the Multiple Sleep Latency Test (MSLT). The
person taking the test is asked to try to take
a nap every couple of hours, and the time it
takes to fall asleep (sleep latency) is recorded.
Anyone who falls asleep within ten minutes probably
has not been getting sufficient sleep at night.
It turns out that—by this standard or more
informal standards—teenagers ordinarily
need eight and a half to nine and a quarter hours
of sleep a night to be fully rested. But surveys
indicate that during the school week, average
sleep time ranges from about seven hours, 40
minutes in 13-year-olds, to barely over 7 hours
in 19-year-olds. Only 15% of adolescents sleep
as long as eight and half hours on school nights,
and 26% say they usually sleep six and a half
hours or less. They try to compensate on weekends
by sleeping nearly two hours longer on average.
The main reason adolescents don’t get
enough sleep is that they simply don’t
make enough time for it, because of early school
hours, homework, part-time jobs, and other demands.
The typical high school student falls asleep
at 11 or later. One reason is that many teenagers
cherish the late night as one of the few times
they have all to themselves. Another, possibly
more important cause is their biological “phase
delay”—a tendency to fall asleep
and wake up later because of changes that occur
at puberty in the internal body clock governing
circadian (24-hour) biological rhythms.
A common circadian rhythm disturbance is known
as delayed sleep phase syndrome (DSPS). Adolescents
with DSPS cannot fall asleep until the early
hours of the morning and often lie awake in bed
for a long time. The problem is especially serious
during the school year, when they have to get
up early on weekdays and may sleep well into
the afternoon on weekends to compensate. Meanwhile,
they feel constantly drowsy during waking hours—except
in summer, when they may sleep from 2 a.m. to
noon. If allowed to persist, the syndrome is
sometimes complicated by conditioning that associates
bed and bedroom with wakefulness. Adolescents
with DSPS are also at risk of developing poor
sleep habits, such as staying up into the wee
hours of the morning doing homework or playing
video games. DSPS often leads to poor schoolwork
and family conflict; it may be an unrecognized
cause of behavior that looks like adolescent
rebelliousness or delinquency. DSPS can also
be mistaken for depression.
Some teenagers are drowsy during the day even
though they seem to be sleeping normal hours.
There could be several reasons for this. Sleep
can be disrupted by drugs (including alcohol
and caffeine), by the rebound effect when a drug
leaves the body, and by medical conditions such
as chronic pain or gastroesophageal reflux (heartburn).
Psychiatric disorders are another cause of disrupted
sleep and daytime sleepiness in teenagers. Either
insomnia (especially difficulty in falling asleep)
or, occasionally, excessive sleep may be a sign
of depression in an adolescent patient. Anxiety
disorders, post-traumatic stress, bipolar (manic-depressive)
disorder, or the onset of a psychosis may also
be contributing to the problem. Involuntary limb
movements, including restless legs syndrome,
are another possible source of unrefreshing sleep.
In trying to understand some adolescent sleep
problems, it is important to recognize that sleep
is not a uniform state. It has a structure sometimes
described as sleep architecture, which is most
evident in the cycle of REM (rapid eye movement)
and non-REM sleep. During non-REM sleep, body
temperature falls, breathing and heartbeat are
regular, and brain waves are slow and rhythmical.
We have little conscious experience at these
times. REM sleep begins about an hour and a half
after we fall asleep and returns four or five
times a night, becoming more frequent toward
morning. This state of consciousness is completely
different physiologically from non-REM sleep,
more closely resembling the waking state. Muscles
(except for the eyes and diaphragm) are almost
completely paralyzed, but brain activity is at
waking levels, and we have vivid dreams. Charting
sleep architecture, especially the pattern of
REM and non-REM periods, is often useful in diagnosing
sleep disturbances and disorders; for example,
the REM sleep of many depressed people begins
unusually early in the night. Specialists can
measure sleep patterns objectively in a laboratory
with a polysomnogram (PSG), which records brain
waves, body movements, breathing, and heart rate.
Two relatively rare but extremely serious causes
of sleepiness in teenagers are narcolepsy and
obstructive sleep apnea. Narcolepsy is a neurological
syndrome that afflicts about 1 person in 2,000.
Its chief symptoms, apart from daytime sleepiness,
are cataplexy—a sudden loss of muscle tone
(going limp) induced by strong emotions—and
sudden attacks of REM sleep in the daytime. Other
symptoms are sleep paralysis (inability to move
although fully conscious during the onset of
sleep or while waking) and hypnagogic hallucinations
(dream-like auditory or visual hallucinations
at the onset of sleep). These symptoms arise
when REM (dreaming) sleep intrudes into waking
periods. The diagnosis is made with the help
of a polysomnogram and the Multiple Sleep Latency
Test.
Narcolepsy has a strong genetic component, although
scientists have not discovered a consistent pattern
of hereditary transmission. In recent research,
it has been linked to decreased numbers of the
brain cells that produce a substance called hypocretin.
But in more than four out of five cases, the
disorder is precipitated by sleep deprivation,
irregular sleep patterns, head trauma, infections,
psychological stress, and other environmental
influences.
Obstructive sleep apnea is the repeated interruption
of breathing during sleep because the passage
to the lungs is physically blocked. Symptoms
include loud snoring, mouth breathing, and morning
headaches as well as daytime drowsiness. Sleep
apnea is diagnosed in the sleep laboratory with
the aid of a polysomnogram. The disorder is common
in middle-aged and elderly people, and it raises
the risk of coronary artery disease, high blood
pressure, and stroke. It rarely occurs in adolescents
unless they are vastly overweight, have enlarged
tonsils, or suffer from a physical malformation
such as an unusually small jaw.
When physicians or other professionals evaluate
sleep troubles in adolescents, they begin with
a detailed clinical history of sleep problems
in the patient and the patient’s family,
as well as interviews with the patient, family
members, and sometimes school staff. They need
a careful description of the patient’s
bedtime routines and environment, including middle-of-the-night
awakenings, wake-up times, morning routines,
daytime alertness, and sleep schedules. It is
often helpful to have the adolescent describe
a typical weekday, weekend day, and vacation
day. The patient should keep a sleep diary for
two weeks. Of course, a medical and psychiatric
history are also essential, and it is important
to know which drugs the patient is taking or
has taken in the past. A physical examination
is necessary to check for sleep apnea. It may
also be useful to have the patient wear a wrist
actigraph, a device about the size of a wrist
watch that measures and times physical activity
in both sleeping and waking hours over a period
of several weeks. Physicians will need to call
on a sleep medicine specialist if the standard
treatments fail, and also in special cases such
as suspected narcolepsy, periodic limb movements,
or sleep apnea.
The key to successful treatment is building
rapport with adolescents and identifying their
concerns and goals. No matter what the cause
of insufficient sleep, education and motivational
counseling will help. Beyond that, treatment
depends on the underlying cause. Many teenagers
will have fewer problems if they are allowed
to start school at a time that accommodates their
biological tendency to delay circadian rhythms.
Several school districts across the country have
taken this measure, and systematic studies in
Minnesota suggest that it is effective. Adolescents
with severe DSPS may need more; well-timed exposure
to bright light and doses of the hormone melatonin,
which regulates the internal body clock, are
often useful.
Antidepressants and psychotherapy (including
cognitive and interpersonal therapies) are recommended
for depression or anxiety. For conditioned (learned)
insomnia, useful approaches include behavior
therapy and improved sleep hygiene—regular
exercise, a regular bedtime, avoiding alcohol
and caffeine. Stimulant medications, including
methylphenidate (Ritalin) and the novel drug
modafinil (Provigil), are used to prevent daytime
sleepiness caused by narcolepsy. Drugs that suppress
REM sleep, such as the tricyclic antidepressants,
may be prescribed for cataplexy. Sleep apnea
can be treated by the use of continuous positive
airway pressure (CPAP)—a device that keeps
the breathing passage open by pumping air directly
into the lungs through a face mask.
Kyle P. Johnson, M.D. is an Assistant Professor
in the Department of Psychiatry, Oregon Health
Sciences University.
Internet Resources
FOR FURTHER READING
Loughlin, G.M., Carroll, J.L., & Marcus,
C.L. Sleep and Breathing in Children: A Developmental
Approach. New York : Marcel Dekker,
2000.
National Sleep Foundation. Adolescent Sleep
Needs and Patterns: Research Report and Resource
Guide. Washington, D.C., 2000.
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