Home » Sleep Disorders » Idiopathic Hypersomnia
January 2021 |  Reviewed by:  John Saito, MD and Seema Khosla, MD

What is idiopathic hypersomnia?

Idiopathic hypersomnia (IH) is an uncommon sleep disorder that is associated with excessive daytime sleepiness despite adequate quantity and normal quality of sleep at night.

If you have IH, you may sleep longer at night than the average person and may struggle to wake up.  Once awake, you may seem confused or drunk (aka “sleep drunkenness”). You may take daytime naps that are several hours long and are often not refreshing. Your intense sleepiness often persists without need or cause and may be dangerous when you operate a vehicle or work equipment.

What are symptoms of idiopathic hypersomnia?

IH often develops in adolescence and is long lasting, though some instances of remission have been reported. IH can cause social and professional complications, including poor work or school performance, reduced earnings, and loss of employment.

Schoolwork, jobs, and relationships often suffer because of the excessive sleepiness. Someone with IH may appear to forget how to do simple activities or have difficulties with memory and brain fog.

Some people with this IH also experience these problems:

  • Headaches
  • Dizziness
  • Cold hands and feet
  • Depression symptoms

How to Diagnose idiopathic hypersomnia?

Self-test

Take the self-test below to see if you may have IH:

Are you very sleepy even though you sleep 8 to 10 hours or more nightly without interruption?

Has this been occurring daily for more than three months? 

Are you very sleepy even after napping, in addition to getting enough sleep at night?

Are these naps unrefreshing?

If your answers to all these questions are yes, then you might have IH, but only a sleep doctor can help make the proper diagnosis.

Diagnosis

Diagnosing IH requires ruling out other common sleep disorders and other factors such as: