There are 78 recognized sleep disorders described in the International
Classification of Sleep Disorders, Diagnostic and Coding Manual,
Published by the American Sleep Disorders Association.
• These cause either difficult initiating or maintaining sleep, or cause
• Three Types: Intrinsic sleep disorders
Extrinsic sleep disorders
Circadian rhythm disorders
INTRINSIC SLEEP DISORDERS
1. Psychophysiological insomnia
People react to situations that are psychologically stressful with bodily
tension or other physical complaints such as upset stomach, headaches.
They learn to associate certain things ( i.e. going to bed) with emotions that
prevent sleep (fear of going to sleep).
They over focus on their sleep problems and that in itself interferes with
2. Sleep state misperception
An honest complaint of insomnia or excessive sleepiness when there is no
objective evidence that sleep is disturbed or lacking.
People in middle or late adulthood can develop this disorder because they
are not able to sleep as long or as well as they could in former years.
3. Idiopathic insomnia
A lifelong inability to get adequate sleep that has no observable cause. We
assume that this difficult is due to an abnormality of sleep-wake control
system sin the brain. It may be due to a problem in the sleep-inducing and –
maintaining systems, or hyperactivity in the arousal system.
This is characterized by excessive sleepiness, abnormal REM sleep,
cataplexy (sudden muscle weakness), hypnagogic hallucinations, and
problems sleeping at night. The cause is not known but researchers are
closing in on a gene that contributes to the disorder. This is the only sleep
disorder that we know is due to a flaw in the primary sleep systems in the
5. Recurrent Hypersomnia
People have recurrent episodes of extreme sleepiness and huge sleep needs.
Episodes of hypersomnia usually last several days to several weeks, and
occur twice a year, on average (although they can occur as many as 12 times
a year). Patients sleep as much as 18-20 yours a day during these episodes,
waking only to eat and go to the bathroom. The best described cause of this
is Klein-Levin syndrome which mostly afflicts teenage boys. Patients with
this syndrome have not only hypersomnia but also binge eating and
6. Idiopathic hypersomnia
The patient complains of excessive sleepiness and prolonged sleep at night.
The sign that sets people with this disorder apart from normal long sleepers
and narcoleptics is that there are numerous episodes of non-REM sleep that
last for up to two hours. For this reason, this disorder is sometimes called
non-REM narcolepsy. Since extreme sleepiness and large sleep need can be
a symptom of many other sleep disorders, like narcolepsy and sleep apnea, it
is important to rule out these before making this diagnosis.
7. Posttraumatic hypersomnia
This is excessive sleepiness that develops as the result of physical injury or
disease in the central nervous system. It can be caused by brain injury,
neurosurgery, infection, or spinal cord injury. The hypersomnia usually
goes away over weeks or months.
8. Obstructive sleep apnea syndrome
In obstructive sleep apnea, breathing is blocked during sleep when the
airway pulls shut. This causes sleep disruption, dropping oxygen levels in
the blood, and cardiovascular problems.
9. Central sleep apnea syndrome
This is a rare type of apnea that occurs not when the throat is blocked but
when the patient can not make the effort necessary to pull air into the lungs.
It is usually the result of problems in the neurological control of breathing,
or with the muscles associated with breathing.
10. Central alveolar hypoventilation syndrome.
During sleep, everyone naturally takes less air into the lungs than when
awake. If there are problems with gas exchange in the lungs (for instance,
caused by emphysema), there may be problems getting enough oxygen
during the night, and sleep is disturbed. Because we naturally take in a
larger volume of oxygen during the day, there may not be similar problems
during the day.
11. Periodic limb movement disorder
PLM disorder occurs when the sleeper periodically moves a limb (usually a
leg) in exactly the same way over the course of the night. A typical
movement would be a kick or flex of the leg every 10 seconds. There
movement disrupt sleep and lead to insomnia and daytime sleepiness.
12. Restless leg syndrome
This is characterized by uncomfortable feelings (tingling, itching, crawling,
pulling, or aching) in the legs right before falling asleep. These feelings are
relieved by moving the legs but return when movement stops. This
interferes with falling asleep and can cause severe insomnia. Usually
patients accumulate large sleep debts after many nights of restless legs, until
the resulting powerful sleepiness overcomes the unpleasant feelings and the
patient sleeps. Once enough sleep debt is worked off, however, the feelings
once again interfere with sleep.
EXTRINSIC SLEEP DISORDERS
• These disorders are those that originate outside the body. These can
be caused by environmental or behavioral factors.
1. Inadequate sleep hygiene
Their habits are not compatible with good sleep or maximum daytime
alertness. Caffeine or other drugs near bedtime, or stressful activities before
bed, are common problems of sleep hygiene.
2. Environmental sleep disorder
Insomnia is due to heat, cold, noise, light, or some other condition in the
sleep environment. The patient’s own sensitivity to the stimulus is usually
more important than the level of the stimulus itself. Sensitivity usually
increases toward morning, when sleep debt is low.
3. Altitude insomnia
This problem occurs when people sleep at high altitudes and are not
accustomed to low air pressure and lower than normal oxygen levels. It is
usually accompanied by fatigue, headache, and loss of appetite.
4. Adjustment sleep disorder
This is a transient insomnia caused by temporary stressful events. To be
diagnosed with this disorder, the insomnia must appear at the same time as
an usually stressful event, and must go away after the event is over.
5. Insufficient sleep syndrome
This is the name given to the experience of someone who persistently fails
to get enough steep or stay normally alert when awake.
6. Limit-setting sleep disorder
Usually found in children, limit-setting sleep disorder occurs when someone
stalls or refuses to go to bed. When an absolute bedtime is set and met, then
the child falls asleep quickly. When limited (bedtimes) are not set and
enforced, or enforced on sporadically, a child’s sleep will be delayed, and
total sleep may not be enough to meet his/her sleep needs.
7. Sleep-onset association disorder
This is another disorder usually associated with childhood. In this disorder,
the individual is unable to sleep unless certain conditions are met: the light
is on. The window is open, the presence of a favorite blanket. When the
conditions are met, the child can sleep easily. This rigidity may not
normally be a problem, except when the sleep conditions cannot be met (a
different room, power outage, blanket is in the wash).
8. Food allergy insomnia
Although the name of this disorder is “food allergy insomnia” it is usually a
food intolerance, such as a lack of enzymes to easily digest milk, and leads
to discomfort and difficulty sleeping.
9. Nocturnal eating (drinking) syndrome
This syndrome is characterized by repeated awakenings with an inability to
return to sleep without eating or drinking. This is usually a disorder of
childhood, but adults can also become conditioned to eating or drinking at
certain times of the night. Once learned, this conditioning leads to repeated
awakenings and reinforcement of the pattern.
10. Hypnotic-dependent sleep disorder
This inability to sleep is caused by tolerance to or withdrawal from a drug
used as a sleep inducer. Such medications commonly include members of
the benzodiazepine group.
11. Stimulant-dependent sleep disorder
Insomnia resulting from dependence on or withdrawal from stimulant drugs
such as amphetamines, cocaine, caffeine, or asthma medications.
12. Alcohol-dependent sleep disorder
As the name suggests, people with this problem depend on alcohol to get to
sleep at night. This usually leads to tolerance – people need more and more
alcohol to get to sleep. they also tend to wake up in the middle of the night
as the alcohol wears off and or dehydration triggers an awakening. For this
disorder to be diagnosed, the patient must have used alcohol to help them get
to sleep for at least 30 days.
13. Toxin affected sleep disorder
This is disturbed sleep because of toxins. In effect the individual is poisoned
by heavy metals or organic poisons, and in some cities, by heavy air
CIRCADIAN RHYTHM SLEEP DISORDERS
These disorders are grouped together because they share a common theme of
disrupting the way sleep occurs over a 24 hour period.
1. Time zone change (jet-lag) syndrome
This is the result of rapidly changing time zones, usually as the result of jet
flight. The disagreement between the body’s internal clock and local time
causes trouble getting to sleep at night, daytime sleepiness, and physical
problems like stomach upset.
2. Shift-work sleep disorder
This transient insomnia or excessive sleepiness results when work schedules
change or are incompatible with non-work sleep-wake cycles.
3. Irregular sleep-wake pattern
This is a disorder in which individuals have not set times for sleeping and
for waking up, with the result that they can have trouble sleeping or waking
when they try to do either. People who are restricted to bed, or who are in a
n environment without a regular daily routine can be at risk for developing
4. Delayed sleep-phase syndrome
This is a disorder in which nightly sleep is delayed until long after the
desired sleep time. This results in sleep-onset association disorder and
trouble waking at the desired time.
5. Advanced sleep-phase syndrome
This is a disorder in which nightly sleep and irresistible sleepiness come
before the desired time, and the patient wakes up earlier than desired in the
6. 24-hour sleep-wake syndrome
People with this syndrome have a kind of sleep pattern usually seen in
experiments where people are isolated from time cues. They sleep as if they
have a free-running biological clock, and have a daily sleep delay of one to
two hours after the previous night’s sleep time.
• These disorders are not primarily disorders of sleep and wake states
per se – rather, they are disorders of partial arousal or disorders that
interfere with sleep stage transitions.
1. Confusional arousals
Also called sleep drunkenness or excessive sleep inertia, this disorder is an
extreme example of the slowness most people feel upon awakening. People
with confusional arousals respond poorly to commands or questions, and
they have major memory impairment of things that have just happened or
happened a short time before. Behaviors are often strange, such as picking
up a lamp and talking because the person believes it is a phone. These
typically occur when someone is aroused from a deep sleep in the first part
of the night or they awaken in the middle rather than at the end of a 90
Sleepwalkers engage in behaviors not usually associated with sleep, such as
sitting up in bed, walking about, or even frantic attempts to “escape”. These
actions are apparently initiated during slow-wave sleep. Sleepwalking may
end by itself when the sleepwalker returns to bed and goes back to sleep, but
if the sleepwalker wakes, he is often extremely confused.
3. Night terrors
This disorder is characterized by sudden arousal from slow-wave sleep with
a piercing scream or cry and signs of intense fear. The individual usually
sits up in bed with eyes open, but is unresponsive to other people or stimuli.
If awakened, the patient is confused and disoriented. People usually can not
remember the event or have vague, dreamlike images of it. This is usually a
disorder of childhood.
SLEEP-WAKE TRANSITION DISORDERS
1. Rhythmic movement disorder
This is a group of repeated movements (usually in the head and neck) that
typically occur immediately before sleep. This disorder is usually found in
children age one or younger. The child may lie prone and repeatedly lift the
head or entire upper body, and then forcibly bang the head back on the
pillow. Or the child may sit against the wall or headboard and repeatedly
bang the back of his/her head against it. Because of this, the disorder is
sometimes called “head banging” but it can involve other movements, such
as a body rolling or rocking on hands and knees.
2. Sleep starts
These are sudden, brief contractions of muscles in the legs, arms, or head,
which occur just as people are falling asleep. These hypnagogic jerks are
felt by most people at some time, but when they are very strong or frequent
they can lead to insomnia.
3. Sleep talking
This problem can be precipitated by emotional stress, fever, or sleep
disorders such as night terrors or even sleep apnea. Sleep talk is usually
benign, although it may bother bed partners or family members. The talk is
usually brief and devoid of emotional content, but it can be a long speech or
infused with anger and hostility. Sleep talking can be spontaneous or
induced by conversation with the sleeper.
4. Nocturnal leg cramps
As the name suggests, these are leg cramps (usually in the calf) that occur
spontaneously during sleep. They may last for only a few seconds or as long
as 30 minutes. The cramps cause arousal and disturb sleep. Their cause is
not well understood.
PARASOMNIAS USUALLY ASSOCIATED WITH REM SLEEP
These are frightening dreams that usually awaken the sleeper from REM
2. Sleep paralysis
This is a common part of REM sleep itself but is a disorder when it strikes
outside REM sleep. Usually, people with sleep paralysis are unable to
perform voluntary movements either right before they go to sleep or upon
waking in the morning. Sleep paralysis most often lasts for several minutes
and then disappears.
3. Impaired sleep-related penile erections
In men, erections are a natural part of REM sleep. When REM-related
erections are not present, it indicates a physical cause of impotence.
Diagnosis of this disorder can be a useful way of differentiating between
psychological and physiological impotence.
4. Sleep-related painful erections
Sometimes the erections associated with REM sleep can be so intense as to
be painful. This may cause nighttime awakenings during REM sleep, and
subsequent sleep loss.
5. REM sleep-related sinus arrest
This is a rare disorder in which the heart will periodically stop beating
during REM sleep. Heart stoppages can last up to nine seconds before
starting again. The cause of this disorder is unknown and is different from
cardiac arrest caused by sleep apnea.
6. REM sleep behavior disorder
In this disorder, the usual REM-associated muscle paralysis is absent, so that
people act out the dreams they are having. Punching, kicking, leaping, and
running from the bed are common.
1. Sleep bruxism
Grinding or clenching teeth during sleep. The sound of grinding teeth can
be unpleasant to others who hear it and can cause excessive tooth wear. It
can also lead to jaw pain and headaches while awake.
2. Sleep enuresis (bedwetting)
Urination at night is found in every infant, but as children are toilet trained,
they become more able to control their bladder at night. Usually, though,
regular bedwetting disappears after the age of five. It is estimated that
regular bedwetting occurs in 40% of 4 year olds, 10% of 6 year olds, 5% of
10 year olds and 3% of 12 year olds. When there are no other neurological,
psychiatric, or urological problems that may cause bedwetting, it is called
“primary enuresis”. There is evidence that primary enuresis is hereditary. A
single recessive gene is thought to be responsible, and there is a high
prevalence of primary enuresis among blood relatives of a child with this
disorder. If both parents were late bedwetters as children, their child has a
77% chance of being a bedwetter. If one parent was a late bedwetter, then
the child has a 44% chance of having frequent bedwettings after the age of
3. Sleep-related abnormal swallowing syndrome
People with this disorder have inadequate swallowing of their saliva while
sleeping. Saliva builds up in the mouth, then flows down the throat and is
breathed into the lungs. This causes choking an coughing and wakes up the
4. Sudden unexplained nocturnal death syndrome
This syndrome is typified by sudden death in healthy young adults while
they sleep. Neither clinical history nor autopsy provides an explanation for
death. The first signs are labored breathing, gasping, and choking, but the
disorder is not sleep apnea. Fibrillation (spasm) of the heart muscle has
sometimes been detected. Southeast Asian men between 25 and 44 years of
age are most often the victims of this disorder, and there are descriptive
terms in many Asian languages that suggest sudden unexplained nocturnal
death syndrome has long been popularly recognized.
5. Primary snoring
Primary snoring is simply loud upper airway breathing sounds without signs
of sleep apnea or diminished breathing.
6. Infant sleep apnea
This refers to central or obstructive apneas during sleep in infants.
Premature infants are more at risk for this disorder than infants born at term.
Infants born before 31 weeks of gestation have about a 50-80% chance of
developing apnea, whereas 7% of infants born at term have apnea.
7. Congenital central hypoventilation syndrome
This is a failure of the automatic control of breathing, so that not enough air
is pulled into the lungs. It is usually worse during sleep than during
wakefulness. It usually gets better over 6 to 12 months, although children
may have to be hospitalized when they get colds or the flu until they are four
or five years old.
8. Sudden infant death syndrome
This is an unexplained sudden death during sleep for which there is no
adequate explanation. The cause is till a mystery although risk factors
include laying an infant on his stomach, respiratory infections, being one of
a multiple birth, or being born to a substance-abusing mother.
9. Benign neonatal sleep myoclonus
This is a jerking of the limbs and trunk, or repetitive stretching. The
disorder is rare but harmless. The cause is not known.
MEDICAL AND PSYCHIATRIC SLEEP DISORDERS
SLEEP DISORDERS ASSOCIATED WITH MEDICAL DISORDERS
Alcohol abuse and dependency commonly disturbs sleep. After 30 minutes
of alcohol consumption, subjective sleepiness increases and stays high for 4
hours. After that, sleep becomes fragmented as the lowered alcohol level
increases arousals. When alcoholics abstain from alcohol, sleep can be
severely disrupted, and the short episodes of sleep they do get are often
plagues by nightmares and other anxiety dreams.
2. Sleeping sickness
Also called African sleeping sickness or Gambian trypanosomiasis, this is a
chronic protozoan brain infection that produces bouts of excessive sleepiness
and delusional like outbursts in quick succession of each other.
3. Nocturnal cardiac ischemia
Chest pains due to atherosclerotic heart disease that keeps the sleeper awake
4. Chronic obstructive pulmonary disease
Lung or bronchial problems that inhibit lung function (like emphysema) can
cause severe insomnia.
Asthma attacks during sleep usually awaken the sleeper.
6. Sleep-related gastroesophageal reflux
Some people wake from sleep with a sour taste in their mouth or with
heartburn. This is because some of the stomach contents have been
regurgitated into the esophagus during the night.
7. Peptic ulcer
The pain of ulcers can waken the sleeper frequently during the night.
8. Fibrositis syndrome
Also called fibromyositis or fibromyalgia, this syndrome is characterized by
diffuse muscle and bone pain, chronic fatigue during the day, and un-
refreshing sleep at night.
SLEEP PROBLEMS ASSOCIATED WITH NEUROLOGICAL
1. Degenerative brain disorders
The many cerebral degenerative disorders can disrupt sleep at night. These
include Huntington’s disease, Alzheimer’s disease, Pick’s disease,
Parkinson’s disease, amyotrophic lateral sclerosis (ALS), and others. Fatal
familial insomnia is a rare, inherited degenerative disorder that begins with
sleep troubles and progresses within a few months of total lack of sleep, and
2. Sleep-related epilepsy
Epileptic seizures can be found in either wakefulness or sleep, and there are
some types that are found mostly in sleep.
3. Sleep-related headaches
Headaches can also strike during sleep, and in some people sleep-related
headache is more common than waking headaches.
SLEEP DISORDERS ASSOCIATED WITH PSYCHIATRIC
Psychoses like schizophrenia and those that are drug-induced are
characterized by delusions, hallucinations incoherence, catatonic behavior,
or inappropriate emotions. Insomnia or excessive sleepiness is also common
in individuals suffering from such psychoses.
2. Mood disorders
Mood disorders include depression, mania, and hypomania. Insomnia is
usually the result, but excessive sleepiness can occur, too.
3. Anxiety disorders
Anxiety disorders are characterized by unusually great anxiety and
avoidance of whatever seems to cause it. Anxiety disorders can create sleep-
onset association disorders or sleep-maintenance insomnia.
4. Panic Disorders
Panic disorders are commonly called phobias: claustrophobia (fear of
enclosed spaces), agoraphobia (fear of open spaces) and the like. Extreme
fear and anxiety can occur unexpectedly and panic episodes can waken
people from their sleep.
PROPOSED SLEEP DISORDERS
• These are sleep problems for which there is not enough information
available to firmly establish them as discrete disorders.
1. Short sleepers
A short sleeper is someone who regularly takes less than 75% of the sleep
time usually required in his or her age group, and feels no negative effects
from this shortened sleep. Psychologically, short sleepers are basically
normal, with a tendency to hypomanic behavior. They are usually smooth,
efficient people who are distinct “non-worriers”.
2. Long sleepers
Long sleepers need substantially more sleep than most people. This usually
means sleeping 10hours or more for adults. The timing and structure of
sleep is normal in true long sleepers –when making this diagnosis it is
important to rule out other problems that might lead to long hours in bed.
Long sleep is usually acquired in childhood, firmly established by
adolescence, and remains a lifelong pattern. Psychologically, long sleepers
tend to be more introverted than others, and often appear mildly depressed or
anxious when interviewed by researchers. They are often described as
3. Sub-wakefulness syndrome
Some people complain about a lack of daytime alertness, but they have no
nighttime sleep disruption and seem to be getting adequate sleep. There is
no objective evidence of severs, excessive sleepiness, but a display of
daytime drowsiness can occur. This syndrome may be a less severe version
of idiopathic hypersomnia, or may be caused by dome other, unrecognized
medical or psychiatric disorder.
4. Fragmentary myoclonus
Myoclonus is manifest by brief, involuntary jerks or twitches. Some people
get this during non-REM sleep throughout the night. The proposed disorder
is very rare and harmless.
5. Sleep hyperhydrosis
Also known as night sweats, this commonly afflicts people when they have a
fever. There are some people, however, who seat heavily at night without
any signs of fever or other disorders. Some people seat excessively during
sleep all their lives. The worst problem is sleep disruption, and people often
have to get up to change pajamas or sheets.
6. Menstrual-associated sleep disorder
There are three forms of menstrual-associated sleep disorders: premenstrual
insomnia, premenstrual hypersomnia, and menopausal insomnia. As these
three names suggest, menstrual-associated sleep disorder can lead to either
less or more sleep than usual.
7. Pregnancy-associated sleep disorder
Pregnancy can also lead to either insomnia or excessive sleep and sleepiness.
Pregnant women usually start the pregnancy feeling excessive need for sleep
and end pregnancy with insomnia due to physical discomfort. In rare cases,
pregnancy and the postpartum period may be associated with nightmares,
8. Terrifying hypnagogic hallucinations
When people fall asleep normally, closed eyes and a state of drowsiness give
way to reverie, and vague thoughts and images flow through the mind just as
sleep is descending. Rarely, these common, unthreatening hypnagogic
images can turn threatening and seem real, partly as a result of how quickly
they follow wakefulness. These hallucinations are common in people with
narcolepsy, who regularly go into REM sleep right after falling asleep.
9. Sleep-related laryngospasm
Very rarely, some people have a spasm of the throat that closes off the
airway and halts breathing during sleep. The result is similar to a single
episode of apnea, but these patients do not have apnea. Typically, the
patient will wake up chocking and jump out of bed, clutching the throat.
Episodes can last anywhere from a few seconds to five minutes. People who
get these laryngospasms typically experience them only two or three times
per year. Drinking water usually speeds the relaxation of throat muscles.
10. Sleep chocking syndrome
This sleep disorder is also rare, but its victims have episodes of choking
almost nightly, and sometimes more than once a night. The patient wakes
with feelings of fear, anxiety, and impending death. Fear is always
associated with the choking, but patients don’t suffer from nightmares, night
terrors, or other forms of nocturnal anxiety attacks. They also don’t suffer
from obstructive sleep apnea. The cause is unknown.