Excessive Sleepiness (Hypersomnias)

Hypersomnias are conditions that are characterized by difficulty or an inability to stay awake when desired (often referred to as excessive daytime sleepiness) and caused by conditions separate from other known sleep disorders that can lead to sleepiness (such as Obstructive Sleep Apnea, or Restless Legs Syndrome). 

Included in this category are:

  • Narcolepsy – Types I and II
  • Idiopathic Hypersomnia
  • Klein-Levin Syndrome
  • Hypersomnia’s due to medical disorders or medications
  • Insufficient Sleep Syndrome

Who gets it and how do you know if you have it?

Excessive daytimes sleepiness can affect anyone, and most commonly is the result of a lack of adequate sleep on a regular basis, or from certain medical conditions or medications.  Determining if one of these factors are the main cause of sleepiness can usually be established after a thorough history obtained by a sleep provider.  In some cases, symptoms may suggest a specific sleep disorder (such as narcolepsy or Klein-Levin Syndrome) that requires further evaluation and specific treatment.

The Epworth Sleepiness Scale (click here to download) is a simple questionnaire you can fill out to assess your level of sleepiness.  A score > 10 usually indicates significant sleepiness.

Individual sleep needs vary from person to person and change over our life span. The National Sleep Foundation (www.sleepfoundation.org/articles/how-much-sleep-do-we-really-need) has provided ranges for recommend amounts of sleep based on age:

  • Newborns (0-3 months): 14-17 hours
  • Infants (4-11 months): 12-15 hours
  • Toddlers (1-2 years): 11-14 hours
  • Preschoolers (3-5): 10-13 hours
  • School age children (6-13): 9-11 hours
  • Teenagers (14-17):  8-10 hours
  • Younger adults (18-25): 7-9 hours
  • Adults (26-64): 7-9 hours
  • Older adults (65+): 7-8 hours

So if you’re experiencing excessive sleepiness and your sleep amount is less than that recommended, it may be that you simply need to increase your sleep time to feel better!


Narcolepsy is considered one of the classic hypersomnia conditions, and much has been learned about it in the last 20 years.  This will be discussed in more detail.

What is it?

Narcolepsy is a relative rare disorder that, despite getting enough sleep on a regular basis, the individual experiences severe sleepiness when they should otherwise be awake.  It is often associated with other symptoms such as sensations of paralysis and / or hallucinations that can occur while falling asleep or waking up.  Narcolepsy is divided into 2 types:

  • Narcolepsy Type I:  severe sleepiness that is associated with the symptom of cataplexy (discussed below) and/or low spinal fluid levels of the chemical called orexin (or hypocretin).
  • Narcolepsy Type II: severe sleepiness without cataplexy or low spinal fluid orexin levels.

Narcolepsy Type I is caused by a loss of the chemical orexin in the brain and it’s felt this leads to the typical symptoms of sleepiness and cataplexy.  The reason for the loss of this chemical is not clear though many researchers believe it’s related to the immune system or inflammation destroying the cells in the brain that produce it. 

The symptom of cataplexy, seen with Type I Narcolepsy, is defined by brief sudden loss of muscle tone while still being awake.  This is usually brought on by strong emotional states (such as laughing or fear) and may appear as suddenly falling to the ground, or an inability to keep the head upright.  Cataplexy is only seen in Type I Narcolepsy.  In Type II Narcolepsy, all features of Type I Narcolepsy are present except for cataplexy.  Individuals with Type II Narcolepsy will have normal levels of orexin in the spinal fluid if that is checked.

Who gets it?

Narcolepsy is a relatively uncommon condition. Type I Narcolepsy occurs in less than 2 in 100,000 persons in the United States (between 0.14% to 0.79% of the population).  It’s unclear how common Type II Narcolepsy is, though most individuals diagnosed with narcolepsy will be Type I.

Narcolepsy usually presents between the ages of 10 and 25, though some will not develop symptoms until later in life with a second peak in presentation around the age of 35.  Sleepiness is usually the first symptom of narcolepsy with the other symptoms presenting later.  Though slightly more common in men, both men and women can develop narcolepsy. 

Symptoms tend to develop gradually and thus individuals with narcolepsy may not present for evaluation until the symptoms become very disabling.

How do I know if I have it?

If you’re experiencing significant sleepiness to the point where it affects your daily life, then it’s worth discussing this with your primary care provider. They will ask you additional questions and help decide if you need to see a sleep specialist for further evaluation.   Remember, the most common cause of sleepiness is lack of enough sleep, so make sure you are getting the recommended amount of sleep as a first step.

Do I need to see a sleep specialist?

If the cause of your sleepiness is not obvious from your history, or if you have some of the symptoms suggesting an underlying sleep disorder, a referral to a sleep specialist is a good idea.  They will ask further questions and decide if testing is needed. 

An overnight sleep study may be ordered if the sleep provider suspects that you may have a primary sleep disorder contributing to the sleepiness.  If there is concern for a problem such as narcolepsy, then a daytime nap test, called a Multiple Sleep Latency Test (MSLT), may follow the overnight sleep study to determine just how sleepy you are and to look for signs of narcolepsy.

How is it treated?

At this time, there is no cure for narcolepsy.  However, the symptoms can be controlled.  The first step with any of the hypersomnias is to ensure you are getting enough sleep and following good sleep practices as outlined in the sleep hygiene section.  For narcolepsy, other recommendations include:

  • Taking scheduled naps
  • Avoiding shift work
  • Avoiding safety sensitive occupations

For control of sleepiness in narcolepsy, stimulant therapy is usually recommended.  There are a variety of different stimulant medications, including a couple of new stimulants based on better understanding of our underlying sleep and wake mechanisms.  These medications are generally needed for life, and your Sleep provider can help determine which is best for you and how best to adjust the dose.  

The management of cataplexy is usually achieved through a combination of avoiding situations that may trigger it and medications.  There are a number of medications that may be used to control cataplexy, and your sleep provider can manage this symptom.

A sleep specialist can help you decide which specific medications would be best to manage symptoms of narcolepsy.  

Our Sleep Medicine team uses advanced technology to diagnose and treat sleep disorders at a variety of locations throughout the community. To schedule an appointment, call 216-778-5864.