Disorders that cause excessive sleepiness are called hypersomnias. This is of course a major hazard when operating heavy machinery (such as driving a car). Some states prohibit those with a hypersomnia from obtaining a driver’s license.

There are three main hypersomnias:

  1. Narcolepsy (the most well-known): uncontrollable attacks of fatigue or sleep during the day
    1. With cataplexy
    2. Without cataplexy
  2. Idiopathic hypersomnia: significant sleepiness despite lots of sleep, falling asleep during the day a la narcolepsy, but with longer, deeper sleep periods
  3. Kleine-Levin syndrome: once, or more, per year, the person
    1. Sleeps at least 11 hours
    2. Binge-eats
    3. Is stricken by irrational thoughts
    4. Is hypersexual


Sleepeducation.com states that this illness afflicts one in every 2,000 people, .05%. Another estimate has it occurring in .03% to .16% of the population.

One should consider other sources of their fatigue if they believe they have narcolepsy. Several other sleep disorders can mimic the fatigue experienced by those who are narcoleptic, but for different reasons. Many other disorders, be they mental or physical, can also create a similar fatigue. And of course, as is true applied to almost every sleep disorder, drug and alcohol use may be the culprit.

It cannot be cured, as so many other mental illnesses. Narcolepsy doesn’t usually have a genetic component. But it’s just about exclusively seen in adults, starting to appear when one is a late teen, as psychotic disorders tend to. Though we don’t know the specific cause of narcolepsy, one can deduce that their is an abnormal balance of excitatory and inhibitory neurotransmission in the central nervous system (CNS).

There are two kinds of narcolepsy:

  1. With cataplexy
    1. Strong emotions prompt sleep attacks that affect muscle tone (normal muscle contraction and tension), while one is awake. One might fall, start slurring their words, even become paralyzed.
  2. Without cataplexy
    1. Other symptoms of narcolepsy, minus loss of muscle tone
  • The symptoms of narcolepsy…
    • Excessive daytime sleepiness (EDS)
      • Feeling significantly tired, though one slept through the night
      • Difficult to stop
      • A quick nap will leave one alert for up to two hours longer
    • Disturbed nighttime sleep
      • 50% of people with narcolepsy oftentimes wake up during the night, and aren’t able to get back to sleep
    • Hallucinations
      • The sense of something else in the room
      • Can cause fear
      • Mainly visual, but can include other senses
      • At sleep-onset
    • Memory issues
      • This arises because something happened when too sleepy to remember it
        • Oftentimes, memory lapses ocurr when one is engaged in a task that doesn’t require much thought
    • Sleep paralysis
      • While waking up or falling asleep
      • Lasts for seconds, up to minutes
      • Can co-occur with hallucinations
  • Diagnosis usually involves entering a sleep facility
    • Usually, one sleeps overnight in a lab (called a polysomnogram)
      • Sensors are attached to monitor heartbeat, brain waves, and other biological processes
      • Afterward, just what kind of disorder is present, is revealed
    • A multiple sleep latency test (MSLT) tests fatigue in the day by asking the patient to take scheduled naps
      • Most narcoleptics take just a few minutes to fall asleep
    • A spinal tap, in rare cases, can be used to determine orexin levels
      • Orexin is a neurotransmitter heavily involved in sleep
  • Pharmacological treatment involves…
    • Stimulants to stay awake
    • Antidepressants to fight hallucinations, cataplexy, and paralysis
  • Lifestyle treatment…
    • Exercise regularly
    • Avoidance of drugs
    • Going to sleep and getting up at the same time each day
    • Possibly, a few short naps throughout the day

Ironically enough, taken altogether, those with narcolepsy don’t necessarily sleep more than average.

Idiopathic hypersomnia

The cause of this disorder appears to come from an endogenous (naturally created) substance that enhances the activity of GABA (a neurotransmitter). It appears in teenage years, up to one’s early 20’s. The intensity of the disease varies over time, about 12.5% spontaneously recover.

  • Symptoms…
    • Foremost: fatigue despite a lot of sleep
    • Poor quality sleep
    • Problems awakening
      • Can require multiple, high-pitched alarms to get up for daily obligations
    • Contrary to narcolepsy…
      • This population can sleep for hours, which they still find unrefreshing
      • They also don’t dream frequently, which narcoleptics do
    • Hypersensitivity to sedating medications and drugs
  • Diagnosis is difficult because this illness can be well-mimicked by others
    • It’s essentially through the same way that narcolepsy is discovered
      • A polysomnogram
      • Multiple sleep latency tests
    • If the picture remains obscured, cerebrospinal fluid (CSF) can be obtained and analyzed
      • Putting thhe CSF in a petri dish with GABA neurons)

Kleine-Levin Syndrome

This is quite a rare neurological disorder. Most of the time, it strikes in adolescence.

Unlike with other sleep disorders, there are no physical tests that can be carried out to diagnose kleine-levin syndrome. Theory suggests that is may be caused by the immune system sending abnormal signals to, and controlling, the hypothalamus. orexin (previously discussed) and histamine are created by the hypothalamus. The disorder may continue for over ten years, episodes occurring cyclically, ranging from days to months.

  • As stated before, Kleine-Levin Syndrome involves…
    • Excessive sleep
    • Abnormal behavior
    • Compromised knowledge of the world
    • Spaced-out or infantile demeanor
    • The afflicted feeling themselves in a fuge of sorts while awake
    • Hypersensitivity
    • Sometimes…
      • Compulsive eating
      • Compulsive sexual behavior
    • Daily activities cease to be completed
      • Inadequate self-care
      • Cannot attend school
      • Cannot work
    • Sleeping most of the 24-hour day
      • They may wake just to eat or relieve themselves
    • Difficulty in communication
    • No residual signs of an episode after it passes
  • Diagnosis of klein-levin syndrome…
  • As for treatment…
    • Stimulants during an episode (has a response rate of over two-thirds of people)
    •  Mood stabilizers (can be effective in 40% of patients), antidepressants, or non-drug treatment to prevent future episodes

Sources: http://www.sleepeducation.org/, http://www.hypersomniafoundation.org/, http://klsfoundation.org/, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3021925/