What is narcolepsy, excessive sleep?

Narcolepsy is a chronic, neurological sleep disorder characterized by excessive daytime sleepiness (EDS), cataplexy and abnormal REM sleep. A person with signs of narcolepsy will experience extreme fatigue and may fall asleep at odd and inappropriate times, such as during work or school. A brief nap is generally refreshing, but the sleepiness re-occur rapidly a few hours later.

Most patients also experience cataplexy, suddenly feeling paralyzed or weak in the head, legs or other body parts especially after excitement or laughing. The disorder is sometimes confused with insomnia due to its characteristic disturbed night-time sleep and with epilepsy because of unexplained sudden falls caused by cataplexy. Another difference with other hypersomnias is that with narcolepsy when the person falls asleep, they generally experience the REM stage of sleep within 10 minutes. Normally, people don’t reach the REM stage until after 90 minutes.

Narcolepsy Symptoms and Diagnosis

Beside excessive daytime sleepiness, patients may display the following symptoms:

Cataplexy – a sudden weakening of the muscles, often triggered by a strong emotion. While cataplexy can manifest as something as minor as a slight slackening of the facial muscles, in extreme cases, a person may experience total collapse or even muscle paralysis. Cataplexy is a cardinal symptom as it almost always indicates that the cause of the narcolepsy is a lack of hypocretin in the brain.

Sleep paralysis – the temporary inability to talk or move when waking; it may last a few seconds to minutes.

Hypnagogic hallucinations – vivid, sometimes disturbing dreamlike experiences that occur while dozing, falling asleep and/or upon awakening.

Automatic behavior – a person continues to function or talk while being half asleep, and awakens with no memory of doing these activities.

Difficulties maintaining sleep – Nighttime sleep is disturbed. Patients often do fall asleep rapidly but are unable to stay asleep for more than a few hours at a time. Nighttime eating and excessive dreaming with motor activity (acting out dreams, see also REM sleep Behavior Disorder) also frequently occur.

Obesity – Many patients with narcolepsy also gain weight as the result of inactivity and sleepiness.

The cause of narcolepsy with and without cataplexy

In most cases of narcolepsy with cataplexy (and in rare cases without cataplexy), all the symptoms are caused by the loss of approximately 70,000 brain cells producing a chemical called hypocretin, a finding made at Stanford University. Visit the Center for Narcolepsy for more details.

In most cases of narcolepsy without cataplexy (and in rare cases with cataplexy), the cause of the symptoms is unclear and the diagnostic is purely based on the result of an abnormal sleep test called the multiple sleep latency test (MSLT).

Treating Narcolepsy

Sleep specialists normally treat narcolepsy with a combination of behavioral changes (primarily scheduling nocturnal sleep and naps) and medications, tailoring the treatment based on the potential cause(s) of the condition, individual symptoms and response to treatments. Changes in work or lifestyle can be helpful. The Narcolepsy Network provides patient education and support.

Treatment duration varies and could require frequent adjustment of medications to get the best response, though complete control of symptoms is rarely achievable. Medications used to treat narcolepsy include antidepressants, stimulants, ADHD medications and sodium oxybate.