Daytime sleepiness, or narcolepsy, is defined as the inability to stay awake and alert during the major waking time of the day, resulting in unintended lapses into drowsiness or sleep. This may occur occasionally in some people when they are overtired, but when it is chronic, it is a serious medical condition.

Narcolepsy is a chronic neurological disorder caused by the brain's inability to regulate sleep-wake cycles normally. At various times throughout the day, people with narcolepsy have fleeting urges to sleep. If the urge becomes overwhelming, they will fall asleep for periods lasting from a few seconds to several minutes. In rare cases, some people may remain asleep for an hour or longer.

Sleeping predisposes an individual to developing serious performance problems in multiple areas of function. In addition, narcolepsy is potentially life-threatening due to accidents at home, at work or while driving or operating machinery. The specialists at Houston Methodist employ a multidisciplinary approach to diagnose and treat narcolepsy.

Symptoms of Narcolepsy
In addition to excessive daytime sleepiness, three other major symptoms frequently characterize narcolepsy:

  • Cataplexy, which is sudden muscle weakness or the sudden loss of voluntary muscle tone (your doctor may say hypotonia)
  • Vivid, often frightening, hallucinations, occurring at the onset of sleep or while awakening
  • Brief episodes of total paralysis (inability to move) at the beginning or end of sleep

Causes of Narcolepsy
The cause of narcolepsy remains unknown, but it is likely that it involves multiple factors interacting to cause neurological dysfunction and sleep disturbances.

Diagnosing Narcolepsy

Narcolepsy is usually not definitively diagnosed in most patients until 10 to 15 years after the first symptoms appear. Our team of sleep specialists at Houston Methodist can help diagnose and offer treatment options unique to each patient’s condition.

Treatment Options

Although there is no cure for narcolepsy, there are treatment options, such as medicines, lifestyle changes and other therapies, which can relieve many of narcolepsy-related symptoms. Treatment for narcolepsy is based on the type of symptoms you have and how severe they are.


Our physicians at Houston Methodist specialize in evaluating and treating narcolepsy at the following convenient locations.