Hypersomnia is a sleep condition that causes excessive sleepiness. Somnolence is a symptom of hypersomnia and other medical conditions characterized by sleepiness.

The terms hypersomnia and somnolence have similar meanings, and it can be difficult to understand the difference. Both names are derived from the Latin word “somnus,” meaning “sleep.”

Somnolence is a symptom of other medical conditions. A medical professional may give you a diagnosis of a condition that causes somnolence.

Hypersomnia is a diagnosable medical condition and can be divided into two categories:

  • Idiopathic hypersomnia is a neurological condition that causes excessive daytime sleepiness and associated symptoms.
  • Secondary hypersomnia is when you experience excessive daytime sleepiness caused by medications, other medical conditions, or sleep disorders.

Read on to learn more about the difference between these two terms, including symptoms, causes, and treatment.

Here’s a look at the symptoms of hypersomnia and somnolence.

Hypersomnia symptoms

The main symptom of hypersomnia is chronic and extreme daytime sleepiness despite getting adequate sleep. Sleep may exceed 9 or 10 hours per night, and naps may exceed 1 hour without making you feel refreshed.

Another common sign is “sleep drunkenness,” where you wake up in a temporary state of confusion. Other signs and symptoms might include:

  • still feeling tired after naps
  • brain fog
  • mood changes like irritability
  • cognitive changes related to poor sleep
  • trouble waking up

Somnolence symptoms

Somnolence is a symptom of other medical conditions, including hypersomnia. It’s characterized by:

  • excessive sleepiness
  • feeling tired all the time
  • associated symptoms, such as poor mental performance

Here’s a look at the causes of hypersomnia and somnolence.

Hypersomnia causes

Hypersomnia can be broken into idiopathic hypersomnia and secondary hypersomnia.

Idiopathic hypersomnia

Idiopathic hypersomnia is a rare neurological condition of unknown cause. Some triggers include:

  • changes in sleep-wake schedule
  • overexertion
  • viral illness
  • mild head trauma

It’s thought that genetic factors, such as certain variations in the gene PER2, may play a role in its development.

Symptoms generally start in adolescence or early adulthood.

Secondary hypersomnia

Secondary hypersomnia is caused by an underlying condition, such as:

These aren’t all the potential causes. It’s also thought that genetics might increase the risk for some people more than others.

Somnolence causes

Somnolence is a symptom of many conditions, such as:

hypersomniasomnolence
medical condition?yesno, symptom of other conditions
subtypesidiopathic and secondarynone
symptoms• excessive sleepiness
• associated symptoms with sleepiness, such as poor concentration		• excessive sleepiness
• associated symptoms with sleepiness, such as poor concentration
causes• idiopathic hypersomnia is a neurological condition of unknown cause
• secondary hypersomnia has many causes, such as medication side effects or underlying medical conditions		• wide range of conditions or lifestyle factors
treatment• primarily medications to improve alertness
• treating underlying conditions		• highly variable based on the underlying cause

For most sleep disorders, a medical professional will start the diagnostic process by:

  • considering your symptoms
  • reviewing your medical history
  • performing a physical exam

The professional may order many types of tests to help look for problems that may contribute to your symptoms. These tests might include:

In some cases, you may need brain imaging, such as MRI or CT scans.

The main treatment for somnolence is treating the underlying condition. Since there’s such a wide range of conditions that cause somnolence, the treatment can also vary significantly.

Idiopathic hypersomnia is primarily treated with medications to increase alertness. Low-sodium oxybate is the only FDA-approved medication.

Other medications that may be prescribed include:

Hypersomnolence is another name for hypersomnia.

Narcolepsy is a sleep condition that causes an extreme tendency to fall asleep throughout the day. Hypersomnia is characterized by excessive sleepiness and associated cognitive changes.

Some people with hypersomnia may sleep more than 9 to 10 hours per night without feeling refreshed.

Next steps if you’re experiencing daytime sleepiness

If you’re experiencing excessive daytime sleepiness, consider the following:

  1. Try to get more sleep and see if your symptoms improve, especially if you’re not getting at least 7 to 9 hours of sleep per night.
  2. Look for ways to improve your sleep hygiene, such as avoiding screens before bed.
  3. Consider changing lifestyle habits that may be contributing, such as high caffeine intake, which can disrupt your sleep quality.
  4. Seek medical attention if getting adequate sleep and good sleep hygiene don’t improve your symptoms.
  5. Follow your healthcare professional’s recommendations for diagnosis and treatment.

Hypersomnia is a medical condition characterized by excessive sleepiness. Somnolence is a symptom of many medical conditions, including hypersomnia. It’s characterized by excessive daytime sleepiness.

You can’t receive a diagnosis of somnolence, but it’s possible to receive a diagnosis of hypersomnia. It’s referred to as idiopathic hypersomnia when it’s not caused by an underlying medical condition.