Sleep Disorders

Narcolepsy and other
hypersomnias (excessive sleep)


A sleep disorder that causes excessive sleepiness, abnormal REM sleep, and frequent daytime sleep attacks.


Idiopathic hypersomnia

Persistent sleepiness lasting more than 3 months without abnormal issues with enter REM sleep.

Idiopathic hypersomnia

Recurrent hypersomnia
(Kleine Levin syndrome)

A rare sleep disorder characterized by persistent episodic hypersomnia and cognitive or mood changes.

Recurrent hypersomnia (Kleine Levin syndrome)

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Narcolepsy is a disabling sleep disorder that mixes the nervous system's messages about when to sleep and when to be awake. Narcolepsy usually starts during the teen years or early adulthood and continues throughout life.

Narcolepsy may cause:

  • Sudden sleep attacks. These may occur at any time during any type of activity, such as eating dinner, driving the car, or carrying on a conversation. These sleep attacks can occur several times a day and may last from a few minutes to several hours.
  • Sudden, brief periods of muscle weakness while a person is awake (cataplexy). The weakness may affect specific muscle groups or may affect the entire body. These periods of muscle weakness are often brought on by strong emotional reactions, such as laughing or crying.
  • Excessive daytime sleepiness.
  • Hallucinations just before a sleep attack.
  • Brief loss of the ability to move when a person is falling asleep or just waking up (sleep paralysis).

Medicines may help prevent sleep attacks and episodes of muscle weakness. But narcolepsy rarely goes away completely.

Beside excessive daytime sleepiness, patients may display the following symptoms:

Cataplexy – a sudden weakening of the muscles, often triggered by a strong emotion. While cataplexy can manifest as something as minor as a slight slackening of the facial muscles, in extreme cases, a person may experience total collapse or even muscle paralysis. Cataplexy is a cardinal symptom as it almost always indicates that the cause of the narcolepsy is a lack of hypocretin in the brain.

Sleep paralysis - the temporary inability to talk or move when waking; it may last a few seconds to minutes.

Hypnagogic hallucinations – vivid, sometimes disturbing dreamlike experiences that occur while dozing, falling asleep and/or upon awakening.

Automatic behavior – a person continues to function or talk while being half asleep, and awakens with no memory of doing these activities.

Difficulties maintaining sleep – Nighttime sleep is disturbed. Patients often do fall asleep rapidly but are unable to stay asleep for more than a few hours at a time. Nighttime eating and excessive dreaming with motor activity (acting out dreams, see also REM sleep Behavior Disorder) also frequently occur.

Obesity – Many patients with narcolepsy also gain weight as the result of inactivity and sleepiness.

In most cases of narcolepsy with cataplexy (and in rare cases without cataplexy), all the symptoms are caused by the loss of approximately 70,000 brain cells producing a chemical called hypocretin, a finding made at Stanford University. 

In most cases of narcolepsy without cataplexy (and in rare cases with cataplexy), the cause of the symptoms is unclear and the diagnostic is purely based on the result of an abnormal sleep test called the multiple sleep latency test (MSLT).

If all the common symptoms of narcolepsy are present, diagnosing the disorder is fairly straightforward. However, if sleep attacks are isolated and there is only mild or no cataplexy, making a correct diagnosis is more challenging. It requires excluding carefully insufficient sleep (sleep deprivation), disturbed nocturnal sleep, insomnia, circadian rhythm disorders, sleep-related breathing (sleep apnea) disorders and psychiatric disorders. A general medical check up excluding anemia, hypothyroidism, heart or other general medical issues is essential.

Sweet Dreams Sleep Services use two main tests to diagnose narcolepsy: the nocturnal polysomnogram and the multiple sleep latency test (MSLT). The polysomnogram continuously records brain waves during sleep, as well as a number of nerve and muscle functions during nighttime sleep. During the test, the narcoleptic will usually fall asleep rapidly, enter REM sleep quickly, and potentially awaken frequently during the night.

For the MSLT, a person is given 4-5 opportunities to sleep every two hours during normal wake times. The specialist uses the test to measure the extent of daytime sleepiness (how fast the patient falls asleep in each nap, also called sleep latency), and also how quickly REM sleep begins, since narcoleptics fall asleep quickly and experience REM sleep early. A positive MSLT (diagnostic for narcolepsy) is obtained when the patient did fall asleep with a mean sleep latency below 8 minutes in the naps, and had at least 2 naps where REM sleep was reached.

In addition to the above, we will commonly performed a blood genetic test for narcolepsy if they suspect hypocretin deficiency called Human Leukocyte Antigen (HLA) DQB1*06:02 typing. Almost 99% of subjects where narcolepsy is caused by a lack of hypocretin are DQB1*06:02 positive, but approximately 25% of the normal US population is positive as well so a negative test is used to exclude hypocretin deficiency.

In some selected cases, especially if Human Leukocyte Antigen (HLA) DQB1*06:02 is positive but the case is unclear, a lumbar puncture may be performed, Cerebrospinal Fluid (CSF) drawn, and CSF hypocretin-1 measured. If CSF hypocretin-1 is below 110 pg/ml, the diagnosis is consistent with narcolepsy caused by hypocretin deficiency. This particular test was first developed at Stanford and is the most definitive test for narcolepsy. Other radiological, genetic or biochemical tests may also be ordered in selected cases.

A polysomnogram continuously records brain waves during sleep, as well as a number of nerve and muscle functions during nighttime sleep. The study is used to evaluate sleep disorders, such as sleep apnea, periodic limb movement disorder (PLMD), narcolepsy and hypersomnia. 

Multiple Sleep Latency Test (MLST)
In the multiple sleep latency test (MSLT), a person is given 4-5 opportunities to sleep every two hours during normal wake times. The specialist uses the test to measure the extent of daytime sleepiness (how fast the patient falls asleep in each nap, also called sleep latency), and also how quickly REM sleep begins. A positive MSLT is obtained when the patient falls asleep with a mean sleep latency below 8 minutes in the naps, and had at least no more than 1 nap (for idiopathic hypersomnia) or 2 naps (for narcolepsy diagnosis) where REM sleep was reached.

Sleep specialists normally treat narcolepsy with a combination of behavioral changes (primarily scheduling nocturnal sleep and naps) and medications, tailoring the treatment based on the potential cause(s) of the condition, individual symptoms and response to treatments. Changes in work or lifestyle can be helpful. The Narcolepsy Network provides patient education and support.

Treatment duration varies and could require frequent adjustment of medications to get the best response, though complete control of symptoms is rarely achievable. Medications used to treat narcolepsy include antidepressants, stimulants, ADHD medications and sodium oxybate.

Idiopathic hypersomnia

Hypersomnia means “excessive sleep.” Patients with idiopathic hypersomnia sleep a reasonable amount at night (at least six hours) but have difficulty waking up and always feel tired and sleepy. In addition to excessive daytime sleepiness, people with idiopathic hypersomnia may:
Sleep enormous amounts every day (10 hours or more)
Display “sleep drunkenness,” such as extreme sleep inertia, difficulties waking up with alarm clocks and feeling groggy for long period of times.

There is little research in the area of idiopathic hypersomnia. Most likely, idiopathic hypersomnia is not a disease but a combination of symptoms with many causes. Excessive sleepiness may be due to:

  • A brain abnormality of unknown cause. For example, some people with idiopathic hypersomnia have low levels of the brain chemical histamine.
  • Low-grade unknown infections (starting after a flu-like illness) or brain damage.

Some patients with hypersomnia may experience other psychiatric conditions such as anxiety, depression or psychosis. In additions, symptoms may be complicated by factors including:

  • Abnormal and irregular sleep schedule and exposure to light
  • Sedative or stimulant medications taken in excess or at the wrong time
  • Having other sleep conditions such as sleep apnea or circadian disturbances

Diagnosing hypersomnia is challenging. Much of the diagnosis process involves ruling out other conditions. We will consider a hypersomnia diagnosis if:

  • You have had symptoms of hypersomnia for at least three months
  • The symptoms are severely affecting your daily functioning

In order to diagnose idiopathic hypersomnia, a person must display symptoms of hypersomnia for at least 3 months and the disorder should have a significant impact on the person's life. If symptoms occur due to medication or a medical disorder, then the person won't be diagnosed with hypersomnia.

Making a diagnosis of idiopathic hypersomnia requires carefullly excluding other causes of daytime sleepiness such as insufficient sleep (sleep deprivation), disturbed nocturnal sleep, insomnia, circadian rhythm disorders, sleep-related breathing (sleep apnea) disorders or medical issues.

A general medical check up excluding anemia, hypothyroidism, heart or other general medical issues is essential. Excluding a psychiatric condition such as depression or generalized anxiety disorder may be difficult and is needed, requiring therapeutic trials.

Other required tests to diagnose idiopathic hypersomnia may include a polysomnogram, multiple sleep latency test (MSLT) and, in rare cases, biochemical or medical tests.

Treatment for hypersomnia is highly personalized, tailored to your specific needs and the severity of your condition. Treatment options include:

  • Cognitive behavioral therapy
  • Treating other sleep disorders you may also be experiencing
  • Medications

Treatment is based on the symptoms displayed and on a careful analysis of their most probable cause(s). Analysis of currently prescribed medications is always needed.

Regularizing of nighttime and daytime sleep through behavioral interventions is a typical first step.

Treating coexisting circadian abnormalities (light therapy, melatonin, etc) or sleep apnea (PAP therapy) may also be needed. The sleep specialist may then prescribe medications to help manage symptoms, and will also recommend continued changes in behavior, such as avoiding night work and activities that delay bed time, as well as changes to the diet and exercise routines. This may also include avoiding alcohol and caffeine.

Medications may include stimulants such as modafinil or amphetamine-like compounds, ADHD medications, antidepressants and sedatives. In case amphetamine like stimulants are prescribed, tolerance and dependence should be carefully monitored as a possible complication.

The Narcolepsy Network provides patient education and support for patients with idiopathic hypersomnia.

Recurrent hypersomnia
(Kleine Levin syndrome)

Recurrent hypersomnia is characterized by recurrent, reversible episodes of hypersomnia often associated with other symptoms that typically occurs weeks or months apart. During episodes, sufferers experience extreme sleepiness and have big sleep requirements, sometimes sleeping as much as 16 to 20 hours a day.

Two types of recurrent hypersomnia are recognized, Kleine-Levin syndrome, and menstrual-related hypersomnia. Menstrual-related hypersomnia is extremely rare. In this case, hypersomnia reoccurs periodically for one week generally around menses. The use of contraceptive hormonotherapy is usually efficacious.

Kleine-Levin syndrome is a rare sleep disorder that most commonly affects teens. People with this neurological disorder experience recurring periods of excessive sleep with behavioral changes. Onset of episodes is often abrupt, and sometimes preceded by flu-like symptoms. Episodes usually last 1-3 weeks. When an episode begins, the patient becomes drowsy and sleeps for most of the day and night, waking only to eat or use the bathroom. When awake but in episode, he or she frequently seems "out of it" and irritable. Childlike behaviors, sexual deshinibition, megaphagia may be observed. They also experience confusion, disorientation, and a complete lack of energy and emotion. People with recent onset KLS cannot attend school, work or care for themselves during episodes; most are bedridden, tired and uncommunicative. Offset of episodes is also often abrupt, and may be associated with a brief bout of insomnia.

Teenage boys account for most cases of KLS. In some instances, those suffering from KLS can go weeks, months or even years without displaying any symptoms, then have a sudden reoccurrence. The cause of KLS is still unknown, but the disorder generally resolves slowly over years. Episodes become less frequent and severe, to resolve in early adulthood.

Diagnosing KLS is admittedly a challenge but can be a relief for a family in search of answers. Because its primary symptom, hypersomnia, is common to a number of disorders, the process by which we diagnose KLS is one of exclusion – ruling out other conditions that share symptoms. As a result, potential KLS patients often will undergo a lot of tests in various specialties: for metabolic problems including diabetes, metabolic encephalopathies and hypothyroidism; an MRI to rule out a lesion, tumor or inflammation as the cause; even for multiple sclerosis, which has aspects that can mimic the symptoms of KLS.

The symptoms of KLS – somnolence, hyperphagia and withdrawal – can mimic those of severe depression, sometimes followed by a brief period of high, manic energy that could lead to a misdiagnosis of bipolar disorder. Because of all these variables, all other possibilities need to be ruled out, and the symptoms must still fit with those commonly observed in KLS patients.

There is no specific, definitive treatment to cure or control KLS. Some aspects of the disease can be managed with medication, such as stimulants to combat the EDS, but this is most effective only once the episodes have already decreased in severity. In some cases, doctors have used lithium and carbamazepine, normally used to treat bipolar disorder, to prevent or shorten episodes. Beyond that, there really isn't much to do to control KLS, other than being as aware as possible of the effects of KLS, how to recognize episodes and to have sufficient support from family and friends.

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