Overview
Idiopathic hypersomnia (IH) is a chronic sleep disorder where a person feels extremely sleepy during the day even after getting a full night of sleep — or even after sleeping much longer than normal. The word 'idiopathic' means doctors cannot find a clear cause. Unlike narcolepsy, people with IH usually do not have sudden muscle weakness or vivid dream-like hallucinations when falling asleep. IH is also sometimes called 'primary hypersomnia' or 'essential hypersomnia.' The main problem in IH is that the brain does not feel refreshed by sleep, no matter how much a person gets. Many people with IH sleep 10 to 12 hours or more each night and still wake up feeling exhausted. A common and very frustrating symptom is 'sleep inertia' — a heavy, foggy, hard-to-shake grogginess after waking up that can last for hours. Some people describe this as feeling like they are 'drunk' or moving through thick fog. This is sometimes called 'sleep drunkenness.' There is no cure for IH, but treatments can help manage symptoms. For many years, stimulant medications were the main option. In 2021, the FDA approved the first medication specifically for IH — low-sodium oxybate (Lumryz or Xywav) — marking a major step forward. Other medications like modafinil, armodafinil, and amphetamine-based stimulants are also commonly used. Research into the causes of IH is ongoing, and new treatments are being studied.
Also known as:
Key symptoms:
Extreme daytime sleepiness despite long or normal nighttime sleepSleeping 10 to 12 or more hours per night (long sleep time)Severe grogginess or confusion after waking up, sometimes called 'sleep drunkenness'Difficulty waking up from sleep, even with multiple alarmsUnrefreshing naps that do not help with sleepinessBrain fog or difficulty concentrating and thinking clearlyMemory problemsFeeling slow or sluggish throughout the dayDifficulty completing daily tasks due to fatigueAutomatic behaviors — doing things on 'autopilot' without remembering themMood changes such as irritability or low mood related to chronic fatigueHeadachesFeeling cold in the hands and feet
Clinical phenotype terms (11)— hover any for plain English
Multifactorial
Caused by a mix of several genes and environmental factors
Juvenile
Begins in the teen years
FDA & Trial Timeline
10 eventsUniversity of Pittsburgh — NA
Harmony Biosciences Management, Inc. — PHASE3
Mahidol University
Centre Hospitalier Universitaire de Nīmes
Nyree Penn — PHASE1
Stanford University — PHASE4
Centessa Pharmaceuticals (UK) Limited — PHASE2
University of Sydney — NA
Alkermes, Inc. — PHASE2
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
4 availableLumryz
indicated for the treatment of excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy
Omeprazole
Pathologic hypersecretory conditions in adults
Xywav
indicated for the treatment of excessive daytime sleepiness (EDS) in patients 7 years of age and older with narcolepsy
Provigil
Improve wakefulness in patients with excessive daytime sleepiness associated with narcolepsy.
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Financial Resources
2 resourcesWAKIX
Harmony Biosciences Management, Inc.
WAKIX — Contact Harmony Biosciences Management, Inc.
Travel Grants
No travel grants are currently matched to Idiopathic hypersomnia.
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5 articlesCaregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.What tests do I need to confirm the diagnosis of idiopathic hypersomnia and rule out other causes?,Which medication would you recommend starting with, and what are the risks and benefits?,Am I a candidate for Xywav (low-sodium oxybate), and how do I access it?,What lifestyle changes or sleep schedule adjustments might help my symptoms?,Are there any clinical trials for IH that I might be eligible to join?,What accommodations can you help me document for school or work?,How will we know if my treatment is working, and how often should I follow up?
Common questions about Idiopathic hypersomnia
What is Idiopathic hypersomnia?
Idiopathic hypersomnia (IH) is a chronic sleep disorder where a person feels extremely sleepy during the day even after getting a full night of sleep — or even after sleeping much longer than normal. The word 'idiopathic' means doctors cannot find a clear cause. Unlike narcolepsy, people with IH usually do not have sudden muscle weakness or vivid dream-like hallucinations when falling asleep. IH is also sometimes called 'primary hypersomnia' or 'essential hypersomnia.' The main problem in IH is that the brain does not feel refreshed by sleep, no matter how much a person gets. Many people with
How is Idiopathic hypersomnia inherited?
Idiopathic hypersomnia follows a multifactorial inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Idiopathic hypersomnia typically begin?
Typical onset of Idiopathic hypersomnia is juvenile. Age of onset can vary across affected individuals.
Are there clinical trials for Idiopathic hypersomnia?
Yes — 16 recruiting clinical trials are currently listed for Idiopathic hypersomnia on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Idiopathic hypersomnia?
25 specialists and care centers treating Idiopathic hypersomnia are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.
What treatment and support options exist for Idiopathic hypersomnia?
2 patient support programs are currently tracked on UniteRare for Idiopathic hypersomnia. See the treatments and support programs sections for copay assistance, eligibility, and contact details.