Alaska Sleep Education Center

What is Idiopathic Hypersomnia? The Burden of Always Feeling Sleepy

Posted by Jennifer Hines

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on Aug 15, 2018 12:20:00 PM


Nearly everybody has experienced those days where you didn't get hardly any sleep the night before (or maybe even a few nights in a row). You're groggy all day, have trouble focusing, your mind drifts as you try to perform mundane tasks, and you may even feel a little more irritable than normal. However, with just one night of good rest, you're back to your normal, focused, alert self in no time.

Now try and imagine what it must be like to live in a state of perpetual drowsiness, chronically plagued with sleepiness. To make matters worse, imagine that you actually sleep just as much, if not more, than the necessary amount, and take frequent naps on top of that. Imagine living a life where you sleep as much as you can, but never get that rested, recharged feeling that sleep is supposed to give you. This is what it's like for those suffering from the rare disorder known as idiopathic hypersomnia.

What is Idiopathic Hypersomnia?

hypersomnia-treatmentIdiopathic hypersomnia (IH) belongs to a class of sleep disorders known as Central Disorders of Hypersomnolence. The International Classification of Sleep Disorders 3 (ICSD-3) describes this group of disorders as those of which "the primary complaint is daytime sleepiness not caused by disturbed nocturnal sleep or misaligned circadian rhythms."

This group of sleep disorders includes narcolepsy types I and II, idiopathic hypersomnia, Kleine-Levin syndrome, insufficient sleep syndrome, and hypersomnia due to medical, hypersomnia due to medication or substance, and hypersomnia associated with a psychiatric disorder.

Many sleep disorders cause symptoms of excessive daytime sleepiness (EDS) usually through interrupted sleep due to sleep related breathing disorders such as obstructive sleep apnea (OSA),  sleep related movement disorders such as periodic limb movement disorder (PLMD), or through a circadian rhythm disorder in which the person's internal body clock is out of sync with the rest of society's.

What makes most of the hypersomnolence disorders different is that none of the usual causes of EDS are present. Sleep is not interrupted from movements or breathing problems, and the sufferer's internal clock is normal. However, even with regular, uninterrupted sleep, the patient rarely feels rested.

Symptoms of Idiopathic Hypersomnia

  • Excessive sleep. 10 or more hours of nighttime sleep plus daytime naps. Not uncommon for sufferers to sleep in excess of 16 hours in a day.
  • Excessive daytime sleepiness

  • Difficulty waking from sleep (even long sleep) even with the aid of multiple alarms, lights, and help from other people.

  • Sleep inertia/drunkenness. An impaired physiological state after awakening, which usually involves confusion, disorientation, and poor coordination.The transition from sleep to wakefulness can be long and difficult to manage. Often, it is easier to return to sleep than to wake up.
  • Taking long, unrefreshing naps. While naps can be taken for several hours, they rarely alleviate sleepiness, and waking from them is often followed by sleep drunkenness.

  • Cognitive dysfunction. This includes memory problems, automatic behavior, and difficulties with concentration and attention.


Causes of Idiopathic Hypersomia

 The causes of IH remain largely unknown as the name suggests––Idiopathic meaning "of unknown cause."

Research is still being conducted into the origins and causes of the disorder.

Diagnosing Idiopathic Hypersomnia

PolysomnographyBecause the disorder is rare and has similar symptoms to other sleep disorders, properly diagnosing it can prove difficult.

Your primary care physician or sleep specialist will usually rate the severity of your EDS symptoms on the Epworth Sleepiness Scale before asking you to partake in a sleep study. They will also want to know whether your EDS or prolonged nighttime sleep has been occurring. For an IH diagnosis the symptoms have to have been recurrent for at least 3 months.

The second step is to have an overnight polysomnogram (PSG) study performed at a sleep clinic. This sleep study is used to rule out other potential sleep disorders that may be causing EDS such as obstructive sleep apnea and periodic leg movement disorder.

During a PSG, the patient is hooked up to several electrodes that monitor brain activity, eye movement, heart rate, blood pressure, body movement, and more.

After a PSG is performed a follow up multiple sleep latency test (MSLT) is conducted, usually the next day. The MSLT measures the same functions as the PSG, but it is conducted during the day through a series of five 20 minute naps spaced 2hours apart. During these nap opportunities, the patient's sleep onset latency and sleep onset REM periods (SOREMPs) are measured.

Sleep onset latency is the time it takes a person to transition from wakefulness to sleep. A normal person's sleep latency is between 5-20 minutes, while a patient suffering from idiopathic hypersomnia is slightly shorter than usual at 8 minutes or less.

Sleep onset REM periods measure how fast a person transitions from wakefulness to the REM cycle of sleep. For most people, the first cycle of REM sleep takes 70-90 minutes to enter.

How is idiopathic hypersomnia distinguished from narcolepsy?

The MSLT is used to differentiate narcolepsy from IH. Narcolepsy type I is usually easily distinguishable because it often has cataplexy associated with it. When cataplexy is not present (as with narcolepsy type II), the MSLT helps distinguish between the two primarily by sleep onset latency and sleep onset REM periods.

In patients with narcolepsy and idiopathic hypersomnia, sleep onset latency occurs quicker than in most other people. However, most patients with narcolepsy (about 80%) have a much shorter sleep onset latency of 5 minutes or less.

Patients with narcolepsy also experience rapid sleep onset REM periods. Often, if the patient also has sleep paralysis this can occur almost immediately, but generally narcoleptics enter REM in under 15 minutes. Sufferers of IH however, usually have normal sleep onset REM periods of 70-90 minutes.

Treatment for Idiopathic Hypersmonia

Currently there is no cure for idiopathic hypersomnia. While IH is similar in some aspects to narcolepsy and some of the treatments for narcolepsy can be used for IH, there are no FDA approved prescription medications for IH. Many of the prescription medications for narcolepsy are used "off label."

Most of the treatments focus on the symptom of EDS, and there is no prescribed treatment for other symptoms such as sleep drunkenness or cognitive dysfunction.

Management of symptoms of IH usually involves sleep hygiene techniques and some medications.

Sleep Hygiene

Sleep hygiene are general practices that are encouraged for nearly all people to avoid sleep difficulty. While not exactly a treatment for IH, many of the practices of sleep hygiene can still prove helpful.

  • Keep a consistent sleep schedule. Go to sleep and wake up at the same times everyday, including weekends.

  • Avoid caffeine and alcoholic beverages if taking amphetamine based medications.


  • Don't over extend yourself. Michelle Chadwick, Founder and Director of Hypersomnolence Australia, says the best advice for sufferers of IH is to "not extend yourself too much or push yourself to do more than is realistic. We should all listen to our bodies and sleep when we know we should. The only difference for someone with IH is that we are not capable of achieving as much in a day as an average person."

Drug Treatments

Stimulant medications used to treat narcolepsy are often used to treat IH. These stimulants include adderall, modafinil, nuvigil, armodafinil, dextroamphetamine, and methylphenidate (Ritalin). These stimulants help promote wakefulness during the day to combat the symptoms of EDS.

Success of stimulant medication in treating IH is still ongoing.

"Although stimulants can sometimes be effective in reducing sleepiness in the sort to medium term," says Chadwick, "they are rarely effective long term, as patients frequently become resistant to their effects.


The largest problem for sufferers of IH is that they live in a near constant state of never feeling completely awake. Constantly feeling sedated can negatively impact lives. Performance at work and school, troubles with social and family lives, and even the dangers of driving or operating machinery, are all hardships hardships for sufferers of IH.

 If you live in Alaska and believe that you may be suffering from a debilitating sleep disorder click the link below for a free 10-minute phone consultation with one of our sleep educators to help determine if a sleep study is right for you.

Chronic Drowsiness

The Alaska Sleep Clinic would like to thank our friends Michelle Chadwick at, and Kasha Oelke from for their contributions to this article.

Topics: sleep disorders

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