Idiopathic hypersomnia is a condition that causes people to be very sleepy during the day even after a full night of sleep. People with the condition have trouble waking up from sleep. They also may wake up confused and disoriented. Naps typically don't lead to feeling refreshed.

Idiopathic hypersomnia is not common, and the cause of the condition is not known.

The need to sleep can strike at any time, including when driving a car or working. This makes idiopathic hypersomnia potentially dangerous.

The condition often develops slowly over time. Diagnosing idiopathic hypersomnia requires ruling out more common sleep conditions. Treatment aims to control symptoms with medicine.

The cause of idiopathic hypersomnia is not known.

You may start by seeing your healthcare professional. Or you may be referred to a sleep specialist.

Here's some information to help you get ready for your appointment.

What you can do

When you make the appointment, ask if there's anything you need to do in advance, such as fasting before having a specific test. Make a list of:

• Your symptoms, including any that seem unrelated to the reason for your appointment.
• Key personal information, including major stresses, recent life changes and family medical history.
• All medicines, vitamins or other supplements you take, including the doses.
• Questions to ask your healthcare team.

Take a family member or friend along, if possible, to help you remember the information you're given.

For idiopathic hypersomnia, some basic questions to ask your healthcare team include:

• What's likely causing my symptoms?
• Other than the most likely cause, what are other possible causes for my symptoms?
• What tests do I need?
• Is my condition likely to be short-term or long lasting?
• What's the best course of action?
• What are the alternatives to the primary approach you're suggesting?
• I have these other health conditions. How can I best manage them together?
• Are there restrictions I need to follow?
• Should I see a specialist?
• Are there brochures or other printed material I can have? What websites do you recommend?

Don't hesitate to ask other questions.

What to expect from your doctor

Your healthcare professional is likely to ask you several questions, such as:

• When did your symptoms begin?
• Have your symptoms been constant, or do they come and go?
• How do your symptoms affect your daily life?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?

What you can do in the meantime

Try not to do anything that seems to worsen your symptoms.

Experts don't know what causes idiopathic hypersomnia, so risk factors are not known. But symptoms usually appear at a younger age, between ages 10 and 30. And women may be more likely to have idiopathic hypersomnia than are men.

To diagnose idiopathic hypersomnia, your healthcare professional asks about your symptoms and reviews your medical history. You'll also likely have a physical exam. You may have several tests to either diagnose idiopathic hypersomnia or rule out other conditions that may be causing the symptoms.

It's important to tell your healthcare team about your family history and what medicines you're taking. People who are diagnosed with idiopathic hypersomnia have excess sleepiness every day for at least three months.

These tools and tests also may help diagnose idiopathic hypersomnia:

• Epworth Sleepiness Scale. This tool helps guide you to rate your sleepiness. It helps your healthcare professional understand how sleep affects your daily life.
• Sleep diary. Your healthcare team may ask you to keep a sleep diary. You log your daily sleep and wake times to help show your sleep patterns.
• Polysomnogram. With this test, you stay in a sleep center overnight. A polysomnogram monitors your brain activity, eye movements, leg movements, heart rate, breathing function and oxygen levels as you sleep.
• Multiple sleep latency test. For this test, you are given multiple daytime nap opportunities. During these naps, the types and stages of sleep you go through are measured. This test usually is done the day after a polysomnogram.

Idiopathic hypersomnia treatment can help ease symptoms.

A common medicine prescribed is the stimulant modafinil (Provigil). This medicine can help you stay awake during the day. Possible side effects of modafinil are headaches, dry mouth, nausea, diarrhea, loss of appetite and weight loss. Armodafinil (Nuvigil) also can treat idiopathic hypersomnia. Possible side effects of this medicine are headache, dizziness, nausea, upper respiratory tract infections, drowsiness and swelling of the spaces inside the nose.

Other medicines suggested by the American Academy of Sleep Medicine include:

• Sodium oxybate (Xyrem, Lumryz).
• Clarithromycin (Biaxin XL).
• Pitolisant (Wakix).
• Methylphenidate (Quillivant XR, Daytrana, others).

More recently, the U.S. Food and Drug Administration approved a medicine with lower sodium called oxybate (Xywav) to treat idiopathic hypersomnia in adults.

Some lifestyle habits may help your symptoms. These include following a regular nighttime sleep schedule, not drinking alcohol and not taking medicines that can affect your sleep.

The main symptom of idiopathic hypersomnia is being very sleepy during the day. Symptoms begin slowly over several weeks or months and may include:

• Having a strong need to sleep.
• Not being able to stay awake and alert during the day.
• Sleeping more than 11 hours at night.
• Having trouble waking up in the morning.
• Being confused, moving slowly and having trouble with coordination after waking up.
• Feeling anxiety after waking up.

People with idiopathic hypersomnia may need to set several loud alarms to wake up in the morning.

People with the condition also may:

• Take naps longer than an hour.
• Not feel refreshed after naps.
• Have trouble with memory and attention.

Rarely, idiopathic hypersomnia can cause someone to fall asleep suddenly during the day.

Some people with idiopathic hypersomnia may experience automatic behavior when they are very sleepy. This can include staring, or they may drive without purpose and later realize that they are miles from home. Automatic behavior also may include writing or saying things that don't make sense. Afterward, people with idiopathic hypersomnia don't remember the behavior.