The pathogenesis (the mechanism that causes a disease) of Idiopathic Hypersomnia (IH) is not well understood, therefore a diagnosis of IH can sometimes take many years. During this time patients can be misdiagnosed and incorrectly treated or ignored altogether and dismissed as being lazy. Diagnosing IH can be difficult as excessive daytime sleepiness can be caused by various disorders and/or conditions as well as numerous medications. A comprehensive medical history and proper clinical evaluation including a thorough physical examination and medical tests are necessary to rule out all other possible causes. These include sleep apnoea, periodic limb movements and other sleep disturbances, insufficient sleep, psychiatric disorders, medication effects, and medical illness such as hypothyroidism. Click here for more information; Daytime sleepiness, finding the cause.

Sleep studies involving a Polysomnography (PSG) followed immediately by a Multiple Sleep Latency Test (MSLT) are carried out to exclude sleep disruptions caused by periodic limb movements and other sleep disorders such as sleep apnoea. A comprehensive medical history and proper clinical evaluation is important. Most people can feel tired, fatigued and at times, excessively sleepy, particularly when they do not get enough sleep. However what sets people with IH apart is that they experience extreme sleepiness despite getting adequate or typically more than adequate hours of sleep. Their sleep may be deep and uninterrupted but it is not refreshing. Symptoms are also persistent, there is no reprieve. Despite extraordinary amounts of good quality sleep people with IH are in an almost constant state of sleepiness.




Managing Idiopathic Hypersomnia

There are no medications specifically for Idiopathic Hypersomnia. Medications used to treat Narcolepsy including stimulants and wake-promoting medications are prescribed to counter daytime sleepiness, however, there are no medications currently available that assist with cognitive dysfunction or extreme difficulty waking up and sleep drunkenness.

Stimulant and wake-promoting medications can be helpful to relieve sleepiness for some people however they are rarely effective long term.
In addition, there are potential unpleasant side effects, which can include sleep deprivation, heart problems and anxiety. The mechanism of action of wake-promoting medications such as modafinil/armodafinil is not completely known, they appear to influence brain chemistry that increases wakefulness. These medications can interact with hormonal birth control to make it less effective, in rare cases it can result in a life-threatening rash, and it is sometimes limited by associated headache.



Idiopathic Hypersomnia Treatment

Some people with IH find a combination of medication and lifestyle changes, including improving general health, career changes and other lifestyle adjustments are helpful in managing their symptoms. Lifestyles changes can be difficult to initiate (and maintain) for people with chronic illness. If you are struggling with this there are therapies designed to help build and maintain practical strategies that affect positive changes to quality of life. Ask your doctor for a referral to one of these specialist therapists.

Dexamphetamine - read our news post "Why is my Dex not working"?
Modafinil and Armodafinil - read our news post "Modafinil/Armodafinil - Birth Control and Pregnancy"

Click here to view and download a copy of our IH Factsheet
Our Factsheet was written by HA's director Michelle Chadwick and has been vetted and is endorsed by Professor Ron Grunstein, MBBS, MD, PhD, FRACP  and international Idiopathic Hypersomnia researcher Professor Karel Šonka MD, DSc.


What it does and doesn't tell a sleep physician 


The multiple sleep latency test (MSLT) tests for excessive daytime sleepiness by measuring how quickly you fall asleep in a quiet environment during the day. The MSLT is a tool currently used to help in the diagnostic process for narcolepsy and idiopathic hypersomnia.

A MSLT immediately follows an overnight polysomnogram (PSG). An overnight sleep study (PSG) is performed to rule out other sleep disorders such as obstructive sleep apnea and periodic limb movement disorder etc as the cause of a patient’s excessive daytime sleepiness. 

Note: a MSLT does not confirm idiopathic hypersomnia. Please read the full document for more information:




Dr Johns was the Founding Director of the Sleep Disorders Unit at Epworth Hospital, Melbourne, Australia. Dr Johns developed the Epworth Sleepiness Scale (ESS) initially so he could assess the daytime sleepiness of patients in his own private practice.

The ESS was first published in 1991. The questionnaire was subsequently modified slightly in 1997. It has become the most frequently used method worldwide for assessing a person’s average level of daytime sleepiness in daily life.

The ESS is a simple questionnaire with 8 questions answered by the person undergoing the test. Each question is scored on a scale of 0-3 with the total tallied to a score between 0-24. The higher the score, the higher the person’s level of daytime sleepiness.