Hypersomnia
…the oversleeping disorder.

Hypersomnia is a rather rare sleeping disorder which is more about too much sleep than not enough!

Technically, hypersomnia refers to a set of related disorders that involve excessive daytime sleepiness and, at first sight, appears to be much like Narcolepsy but there are major differences. It is sometimes misdiagnosed as narcolepsy. In many ways the two are similar.

One significant difference is that people with narcolepsy experience a sudden onset of sleepiness, while people with hypersomnia experience increasing sleepiness over time. Also, people with narcolepsy find daytime sleep refreshing, while people with hypersomnia do not.

As we noted, hypersomnia is an uncommon disorder. In general, 5% or fewer of adults complain of excessive sleepiness during the daytime. That does not mean all those who complain of excessive sleepiness have this. There are many other possible causes of daytime sleepiness.

Of all the people who visit sleep clinics because they feel they are too sleepy during the day, only about 5–10% are diagnosed with primary hypersomnia. It generally appears when the patient is between 15 and 30 years old. It does not begin suddenly, but becomes apparent slowly, sometimes over years.

Hypersomnia is characterized by excessive daytime sleepiness, and daytime naps that do not result in a more refreshed or alert feeling. Persons with this disorder are compelled to nap repeatedly during the day, often at inappropriate times such as at work, during a meal, or in conversation. These daytime naps usually provide no relief from symptoms.

This does not include lack of nighttime sleep which is different from feeling tired due to lack of or interrupted sleep at night. People experiencing problems with nighttime sleep may have insomnia, a separate sleep disorder. In people with insomnia, excessive daytime sleepiness may be a side effect.

Patients often have difficulty waking from a long sleep, and may feel disoriented. Other symptoms may include anxiety, increased irritation, decreased energy, restlessness, slow thinking, slow speech, loss of appetite, hallucinations, and memory difficulty. Some patients lose the ability to function in family, social, occupational, or other settings.

Basic causes of Hypersomnia may include:

1. Another sleep disorder (such as narcolepsy or sleep apnea
2. Dysfunction of the autonomic nervous system
3. Drug or alcohol abuse
4. Physical problems such as a tumor, head trauma, or injury to the central nervous system
5. Certain medications, or medicine withdrawal
6. A genetic predisposition
7. …and for some, there is no known cause!

[BUT: The exact causes remain unclear. There is some speculation that in many cases it can be attributed to problems involving the hypothalamus, but there is little evidence to support that claim and “The Diagnostic and Statistical Manual of Mental Disorders”, which presents the guidelines used by the American Psychiatric Association for diagnosis of disorders, states that symptoms must be present for at least a month, and must interfere with a person's normal activities. Also, the symptoms cannot be attributed to failure to get enough sleep at night or to another type of sleep disorder.]

There are two main categories of Hypersomnia:

1. Primary (sometimes called idiopathic hypersomnia) is characterized by excessive daytime sleepiness over a long period of time. The symptoms are present all, or nearly all, of the time.
2. Recurrent (sometimes called recurrent primary hypersomnia).

Recurring hypersomnia involves periods of excessive daytime sleepiness that can last from one to many days, and recur over the course of a year or more but not all of the time!

The primary difference between this and primary hypersomnia is that persons experiencing 'recurring' will have prolonged periods where they do not exhibit any signs of hypersomnia, whereas persons experiencing 'primary' are affected by it nearly all the time.

One of the best documented forms of recurrent hypersomnia is Kleine-Levin syndrome, although there are other forms as well. Kleine-Levin syndrome is present in about three times more males than females.

People with Kleine-Levin syndrome have symptoms that differ from the symptoms of other forms of hypersomnia. These people may sleep for 18 or more hours a day. In addition, they are often irritable, uninhibited, and make indiscriminate sexual advances.

People with Kleine-Levin syndrome often eat uncontrollably and rapidly gain weight, unlike people with other forms of hypersomnia. This form of recurrent hypersomnia is very rare.

Both are characterized by the same signs and symptoms and differ only in the frequency and regularity with which the symptoms occur.

Hypersomnia is not an easy diagnosis. Most of us nap during the day at some time but this is much more, often triggered by another problem, and although fairly unusual, can be very disturbing.

If you think your oversleeping may be a problem, talk to your doctor.

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