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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, incorrectly treated, 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 illnesses 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 are 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

As the cause of IH is unknown, there is no cure nor medication specifically designed to treat it. Medications used to treat narcolepsy, including stimulants and wake-promoting medications, are prescribed to help manage daytime sleepiness. Unfortunately, these medications don't address all symptoms, such as cognitive dysfunction or the extreme difficulty waking up and sleep drunkenness.

Stimulant and wake-promoting medications can be helpful to relieve sleepiness for some people, but they are rarely effective long-term and generally don’t provide quality wakefulness. There are also potentially unpleasant side effects, which can include sleep deprivation, heart problems and anxiety.

The mechanism of action of wake-promoting medications such modafinil and armodafinil is not completely known but they appear to influence brain chemistry that increases wakefulness.

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IMPORTANT: Modafinil and armodafinil can interact with hormonal contraception, such as birth control pills, patches, and vaginal rings, making them less effective. If you take modafinil or armodafinil and use hormonal birth control, please speak with your doctor for more advice. You may also find our factsheet on modafinil/armodafinil helpful.

Many people with IH benefit from a combination of medication and lifestyle changes including improving general health, career changes, and other lifestyle adjustments are helpful in managing their symptoms. Lifestyle changes can be difficult to initiate and maintain for people with chronic illnesses and may require the assistance of a specialist therapist and peer support.


You may also find this information helpful: 

'LIFE AFTER DIAGNOSIS - Insights into how to live your best life' is a 3 part presentation and discussion on ‘Improving overall health and wellbeing and how that can have a positive impact on managing IH symptoms’. There are detailed PDF's available that include the words and the slides from the presentations and much more information. You can find links to those PDFs here.


Dexamphetamine - read our news post "Why is my Dex not working"?  This information is also relevant to other amphetamine-based medications, eg; methylphenidate (Ritalin).


Modafinil and Armodafinil - read our news post "Modafinil/Armodafinil - Birth Control and Pregnancy"

Xyrem - How to access Xyrem (Sodium Oxybate) in Australia and Why is Xyrem not TGA registered (approved) or PBS listed?

Tips for Living with Idiopathic Hypersomnia - Practical advice for Patients, Carers, and treating Doctors.

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.

For a full range of resources

We have put together a general list of frequently asked questions that you may find helpful


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.

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