Hypersomnia is a sleep disorder in which a person is excessively sleepy and sleeps extensively.

Hypersomnia is classified as a sleep disorder and is characterized by excessive sleepiness and extensive durations of sleep. Hypersomnia, also known as hypersomnolence, is a neurological illness with a wide variety of causes. Hypersomnia can cause considerable distress and negatively impact someone functioning in several aspects of their life, including academic, occupational and social settings.

What is Hypersomnia?

Hypersomnia refers to repeated incidents of extreme sleepiness during the day or extended nighttime sleep. People with hypersomnia are not fatigued because of disrupted sleep at night but rather, they may feel obliged to frequently nap throughout the day. The urge to nap often comes during inopportune times, like while driving, eating or mid-conversation. If naps are taken, they fail to rejuvenate and energize a person and do not offer a reprieve from symptoms. Hypersomnia is usually detected during the teenage years or early adulthood.

Types of Hypersomnia

The International Classification of Sleep Disorders categorizes hypersomnia disorder into eight different types. These types can be subdivided into primary and secondary categories. Primary categories refer to hypersomnia that exists independent of any other conditions, while secondary categories denote that hypersomnia is rooted or linked to another condition.

Narcolepsy Type 1 

Narcolepsy is a sleep disorder characterized by excessive fatigue and uncontrollable bouts of sleep and is classified into two different types. Narcolepsy type 1 is exemplified by extreme sleepiness during the day along with cataplexy — a condition where strong emotions or excessive laughter can cause someone to collapse suddenly, although still remaining conscious — an abrupt loss of muscle tone, or a shortage of hypocretin — a neuropeptide that controls awakening. In some cases, an individual may possess both cataplexy and depleted levels of hypocretin in addition to excessive fatigue. People who have narcolepsy with cataplexy experience a loss of muscle tone while they are awake. They will suddenly lose the ability to control their muscles, resulting in slurring, falling, or being too incapacitated to move. An incident of cataplexy can last anywhere from a few seconds to several minutes and is frequently initiated by strong positive emotion, such as laughter and enthusiasm.

Narcolepsy Type 2

An individual with narcolepsy type 2 possesses all the symptoms of narcolepsy but lacks the cataplexy symptom. This type of narcolepsy is distinguished by excessive sleepiness but without incidents of weakened muscle tone. Narcolepsy type 2 is not typically as severe as narcolepsy type 1.

Idiopathic Hypersomnia

Idiopathic hypersomnia is very rare and refers to hypersomnia that has no actual cause. Individuals diagnosed with idiopathic hypersomnia never feel completely rested and are constantly drowsy. These people often obtain more sleep than is generally recommended but can never find relief for their constant fatigue. There is no definitive reason why people with idiopathic hypersomnia have such an excessive need for sleep.

Kleine-Levin Syndrome 

Kleine-Levin Syndrome (KLS) is a rare disorder characterized by the need for excessive amounts of sleep, as well as altered behavior, such as hypersexuality. Individuals with KLS may sleep for 20 hours per day, earning it the alias “Sleeping Beauty” syndrome.

Secondary Categories of Hypersomnia

Secondary categories of hypersomnia refer to:

  • Hypersomnia due to a medical condition, such as a head injury, neurodegenerative disease or neuromuscular disorder.
  • Hypersomnia due to a medication or substance, including prescription medications or drugs.
  • Hypersomnia associated with a psychiatric condition, such as depression.
  • Insufficient sleep syndrome, which is when individuals do not get recommended amounts of sleep on a nightly basis.

Symptoms of Hypersomnia

Individuals have trouble awakening from an extended sleep and experience symptoms such as:

  • Anxiety
  • Increased impatience and annoyance
  • Reduced energy
  • Fidgety and restless
  • Impaired thinking and speech
  • Reduced appetite
  • Impacted memory
  • Hallucinations

Causes of Hypersomnia

There are numerous potential causes of hypersomnia, including:

  • Physical injury, such as head trauma or damage to the central nervous system.
  • Neurological disease such as multiple sclerosis, epilepsy or Parkinson’s disease.
  • Hormonal imbalance
  • Drug or alcohol abuse
  • Prescription medication, such as tranquilizers or antihistamines.
  • Sleep deprivation or other sleep disorders, including narcolepsy and sleep apnea.
  • Medical conditions such as obesity or depression.
  • Genetic predisposition

How is Hypersomnia Diagnosed?

A person experiencing excessive daytime sleepiness will usually go to their physician, who will inquire about sleeping habits and a medical history. Physicians will usually order some blood tests and sleep studies for further assessment. Sleep tests may include the Epworth Sleepiness Scale, which rates symptom severity, and a polysomnogram and multiple sleep latency tests, which eliminates other potential sleep disorders.

In order to receive a hypersomnia diagnosis, someone must experience extreme sleepiness for at least thirty days in acute disorders and at least ninety days in persistent disorders. Extended sleep incidences must occur at least three times per week and produce emotional distress and impairment in significant areas of life functioning.

Hypersomnia cannot be attributed to an insufficient amount of sleep and excessive sleepiness cannot occur as part of another sleep disorder. Finally, hypersomnia cannot be due to physiological impact of a substance or other medical condition.

Who is at Risk for Hypersomnia?

Individuals who have situations or circumstances that make them fatigued during the day are most at risk for hypersomnia. Some conditions that cause daytime sleepiness include sleep apnea, depleted thyroid levels, cardiac issues, adrenal functioning, and circumstances of the brain. People that habitually smoke or drink alcohol are also at risk of hypersomnia.

Hypersomnia Statistics

For the purpose of finding treatments for hypersomnia, research has been conducted and some statistics from studies include:

  • Nearly half of all adults will experience hypersomnia symptoms at some point during their lives.
  • The National Sleep Foundation estimates that up to 40% of individuals have periodic symptoms of hypersomnia.
  • Hypersomnia impacts men more often than women
  • Hypersomnia disorders impact 15-30% of those with sleeping difficulties
  • 4-6% of the general population has hypersomnia
  • Idiopathic hypersomnia is 10 times less common than narcolepsy

If you are experiencing symptoms of hypersomnia, you can speak with a therapist who specializes in topics associated with sleep disorders.  If you or someone you know is struggling with a substance use or co-occurring disorder like hypersomnia, help is available. At The Recovery Village, a staff of professionals provides a number of treatment programs for addiction and co-occurring disorders. Call and speak with a representative to learn more about which treatment program could work for you.

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Editor – Jennifer Kopf
Jennifer Kopf is a Florida-based writer who likes to balance creative writing with helpful and informative pieces. Her passion for helping people has translated into writing about the importance of treatment for substance use and mental health disorders. Read more
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Medically Reviewed By – Tracy Smith, LPC, NCC, ACS
Tracy Smith is a Licensed Professional Counselor, a Nationally Certified Counselor, an Approved Clinical Supervisor, and a mental health freelance and ghostwriter. Read more
Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.