What is Idiopathic Hypersomnia?

Posted by Darian Dozier on Dec 15, 2023 7:07:00 PM

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Idiopathic hypersomnia is a chronic neurological disorder that is characterized by an insatiable desire to sleep that is not fulfilled by a regular night of sleep. Those with the idiopathic hypersomnia sleep for longer than the normal amounts of time of sleep each night. However, despite this, they still feel incredibly tired the next day. They may take long naps, but don't feel any better when they wake up. It is almost like they are experiencing untreatable sleep deprivation. Continue reading to learn more about the symptoms, diagnosis, and causes of idiopathic hypersomnia, and what you can do to treat it.

What are the symptoms of idiopathic hypersomnia?

The main symptom of idiopathic hypersomnia is excessive daytime sleepiness even though one received the amount of sleep that they needed the night before. Not only do individuals normally receive the recommended number of hours of sleep, but they often sleep longer than that and still feel tired. Additionally, symptoms can include feeling unrefreshed or unrestored after sleep, having severe sleep inertia, sleep drunkenness when they wake up, being extremely difficult to awake from sleep, and have feelings of grogginess and disorientation whenever they wake up. Those without sleep disorders may wake up and briefly want to return to sleep, however, those with idiopathic hypersomnia have a much stronger desire to return to sleep, and are more difficult to arouse from sleep. Sleep seems to leave behind a type of mental fog that can remain present in the few hours following that those with idiopathic hypersomnia are still awake.

People with idiopathic hypersomnia can sleep more than 11 hours out of every 24 hours. The disorder is chronic, and the symptoms can be unrelenting. And there is no medication that can directly control the symptoms. This makes it difficult for them to hold down jobs, remain in school, maintain marriages or relationships, and engage socially with individuals in their community. Even with medication, patients may still struggle with these activities daily.

Symptoms can appear in the mid to late teens or early 20s. Symptom intensity often varies, and can worsen just prior to menses in women. Symptoms may spontaneously go away in 10 to 15% of patients.

Sleep is normally described as “deep”. Arousal from sleep is usually extremely difficult in regular people, but this period of sleep lasts for about 45-90 minutes. In those who have idiopathic hypersomnia, they are in this stage of sleep for much longer than the average person. This is why they are always difficult to arouse, whereas a person without idiopathic hypersomnia can be aroused in pretty much every other sleep stage. This means that individuals have to use several alarm clocks to wake themselves up from sleep, and have to participate in intense morning rituals that ensure the person is awake for work or school.

Another hypersomnia disorder, narcolepsy, can often be cured by taking naps. This is because those individuals feel refreshed after a nap. However those with idiopathic hypersomnia never feel refreshed after taking a nap.

The symptoms of idiopathic hypersomnia and the medications used to treat it may cause difficulty with anesthesia and hospital care period This is why it's important for anesthesia to come up with a care plan for emergencies or planned anesthetic situations.

Diagnosing idiopathic hypersomnia

Proper diagnosis is key to establishing a good treatment plan that is beneficial for the individual. Diagnostic criteria includes:

  • excessive daytime sleepiness for at least three months
  • the exclusion of medications as a cause
  • a thorough medical history, physical exam, and other medical tests that can rule out other conditions
  • the exclusion of sleep rhythm disturbances
  • overnight sleep test, or polysomnography, immediately followed by the multiple sleep latency tests. It is ideal that these tests be performed in accredited sleep laboratory.


Idiopathic hypersomnia is and disorder of the brain and nervous system whose cause is not known. There may be multiple causes which applies to a subset of the idiopathic hypersomnia population. One current hypothesis is that there seems to be an overproduction of a molecule present in cerebrospinal fluid that acts like a sleeping pill or an anesthetic. The composition of this molecule is yet to be determined, however, it is known to interact with GABA, which is a inhibitory a transmitter in the brain. In the presence of this substance, the inhibitory and sleep-promoting actions of GABA are enhanced more than they normally would be. Research is continuing to identify the small molecule and determine its role in idiopathic hypersomnia.


Medications for idiopathic hypersomnia include three broad types of medications. One is a stimulant, one is a non-stimulant wake promoting medication, and another is an oxybate.

Simulants are approved for the treatment of sleepiness and narcolepsy, and include dextromethorphan and methylphenidate. Stimulants may be effective, however, side effects include moving behavior changes, dental problems, and heart problems.

Non stimulant weight promoting medications including Modafinil and armodafinil. It's not really known how these medications work, however they appear to influence the brain chemistry in a way that increases wakefulness, especially the neurotransmitter dopamine.

Sodium oxybate is a medication that can be taken at bedtime that promotes deep sleep and can improve daytime sleepiness and cataplexy in those with narcolepsy. It was reported that sodium oxybate improved daytime sleepiness and people with idiopathic hypersomnia treated in clinic to the same degree as those with narcolepsy type one. Has also reported that oxybate has been able to improve severe sleep inertia in 71% of those with idiopathic hypersomnia. It may also reduce disruptive sleep, which is a subgroup of what idiopathic hypersomniacs face.

There are other medications available, but many of them have not been FDA approved for idiopathic hypersomnia specifically. It is important to speak with the physician or healthcare provider on the best option for you if you think that you are experiencing idiopathic hypersomnia.

Individuals struggling with idiopathic hypersomnia should click the orange button below to take a free online sleep test to talk with one of our sleep health professionals.

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