Hypersomnolence is excessive sleepiness. People with hypersomnolence, as opposed to fatigue, often fall asleep unintentionally. Once hypersomnolence has been confirmed, the first cause to be ruled out should be inadequate sleep time (chronic insufficient sleep). Most people require at least 7 hours of sleep per night and often closer to 8, men generally requiring less than women.

Hypersomnia is fairly common, with nearly 5% of the population affected. The age groups most affected by hypersomnia are teenagers and young adults. As with most sleep disorders, hypersomnia is underreported because many people inaccurately believe that always feeling sleepy and taking naps are normal behavior.

There are perhaps 5 types of hypersomnia:

  1. Post-traumatic hypersomnia may arise from a head injury or a traumatic incident involving the central nervous system. It is usually associated with related symptoms such as headaches, fatigue, memory impairment, as well as difficulty concentrating. Usually experienced immediately after the accident, some cases are delayed for more than a year. Duration of symptoms may last only a short time, can continue for months or years, or can remain indefinitely.
  2. Recurrent hypersomnia. Kleine-Levin Syndrome, a disorder that causes individuals to sleep for extended periods of time followed by a normal period of alertness, is a type of recurrent hypersomnia. The length of the episode or the time period between episodes varies. It may or may not be accompanied by other symptoms such as overeating and hypersexuality.
  3. Idiopathic (primary) hypersomnia. This category is for those cases for which a cause cannot be determined. This type of hypersomnia is similar to narcolepsy in that the individual is excessively sleepy, falls asleep at inappropriate times, frequently takes naps, and sleeps at night for greater than 10 hours. In some cases of idiopathic hypersomnia, cataplexy and hypnagogic hallucinations may be present and resemble the symptoms of narcolepsy. However, in idiopathic hypersomnia there are insufficient sleep onset REM periods to justify the diagnosis of narcolepsy. Idiopathic hypersomnia is a lifelong disorder with no tendency to remit spontaneously.
  4. Normal hypersomnia. A “normal” hypersomniac is one who simply requires more than 10 hours sleep each day. There is a genetic predisposition to this type of hypersomnia. These individuals are typically called “long sleepers.”
  5. Psychiatric hypersonmia is when excessive daytime sleepiness (EDS) is judged to be related to a mental disorder. This is a challenging area because the EDS may also produce mental disorders (mood disorders) as a complication of hypersomnia. A sleep study can help determine which came first, the chicken or the egg.

If lack of sleep is a problem, total sleep time should be increased before other diagnoses are considered or while other possibilities are being explored. Severe depression and drugs causing sleepiness should also be excluded. If sleep time appears adequate, sleep disorders from the hypersomnia group should be suspected. These include:

  • Sleep apnea (or sleep apnoea) syndrome
  • Narcolepsy
  • Primary CNS hypersomnolence
  • Periodic movements of the legs during sleep (PMLS), also known as nocturnal myoclonus. A condition where the legs move every 40 seconds or so, producing brief arousals. Commonly seen in the first few weeks on nasal CPAP, but it is not understood why. PMLS is another cause of daytime sleepiness.
  • rare forms of hypersomnolence such as post traumatic hypersomnolence, periodic hypersomnolence (Kleine-Levin Syndrome, idiopathic recurring stupor), or post-infectious hypersomnia.

CNS hypersomnolence is suspected to be related to narcolepsy. The major difference is that CNS patients do not show cataplexy or the presence of dreams (REM sleep) during nap opportunities.


Signs, symptoms & indicators of Hypersomnolence

Symptoms - Mind - Emotional  

Depression with fatigue

Symptoms - Sleep  

Difficulty getting out of bed



Conditions that suggest Hypersomnolence




Depression and hypersomnolence are often seen together.

Risk factors for Hypersomnolence


Current Smoker

Smoking was associated with difficulty initiating sleep and with a constellation of symptoms suggestive of sleep fragmentation. Sleep disturbance may be more prevalent among smokers due to the stimulant effects of nicotine, nightly withdrawal, an increased prevalence of sleep disordered breathing relative to nonsmokers, and/or an association with psychological disturbance. These results have important clinical and public health implications for reduction of the disease and disability associated with smoking and sleep disturbance.

Among both males and females, smoking was associated with difficulty initiating sleep, and difficulty waking up. Excessive daytime sleepiness was related to smoking only for females while nightmares and disturbing dreams were related to smoking only among males. [Quarterly Journal of Medicine 1974, 43/172: pp. 525-536]

Environment / Toxicity  

Magnesium Toxicity

The symptoms of magnesium toxicity include central nervous system depression, muscle weakness, fatigue and sleepiness.

Recommendations for Hypersomnolence


Alcohol Avoidance

Alcohol may make this condition worse.


Conventional Drugs / Information

Ritalin or other stimulant drugs have been used successfully in controlling the need to sleep during the day. One such is Provigil, a wake-promoting drug which improves wakefulness in patients with excessive daytime sleepiness (EDS) associated with narcolepsy or hypersomnia, without affecting nighttime sleep.

Idiopathic hypersomnia is usually treated with stimulant medications such as amphetamine, methylphenidate, and modafinil. These drugs may not work as well for this condition as they do for narcolepsy.


Increased Sleep

Avoid working at night or social activities that delay bedtime.


Weak or unproven link
Strong or generally accepted link
Strongly counter-indicative
Likely to help
Highly recommended



Usually Chronic illness: Illness extending over a long period of time.

Nervous System

A system in the body that is comprised of the brain, spinal cord, nerves, ganglia and parts of the receptor organs that receive and interpret stimuli and transmit impulses to effector organs.


Arising spontaneously or from an obscure or unknown cause.


A cause of daytime sleepiness due to an inherited disorder of the control of dreaming sleep. It should be differentiated from sleep apnea, periodic leg movements and other rarer causes of daytime sleepiness.


An abrupt temporary loss of voluntary muscular function and tone, sometimes evoked by an emotional stimulus such as laughter, pleasure, anger, or excitement.


A false or distorted perception of objects or events, including sensations of sight, sound, taste, smell or touch, typically accompanied by a powerful belief in their reality.


Cessation of breathing.


Central Nervous System.

Nasal CPAP

The process of delivering a continuously raised airway pressure via a mask on the nose. Hence nasal Continuous Positive Airway Pressure treatment.


An essential mineral. The chief function of magnesium is to activate certain enzymes, especially those related to carbohydrate metabolism. Another role is to maintain the electrical potential across nerve and muscle membranes. It is essential for proper heartbeat and nerve transmission. Magnesium controls many cellular functions. It is involved in protein formation, DNA production and function and in the storage and release of energy in ATP. Magnesium is closely related to calcium and phosphorus in body function. The average adult body contains approximately one ounce of magnesium. It is the fifth mineral in abundance within the body--behind calcium, phosphorus, potassium and sodium. Although about 70 percent of the body's magnesium is contained in the teeth and bones, its most important functions are carried out by the remainder which is present in the cells of the soft tissues and in the fluid surrounding those cells.

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