Narcolepsy 

     Narcolepsy is a sleep disorder that has several symptoms.  The main symptoms consist of excessive daytime sleepiness and episodes of muscle weakness during times of emotion (happiness, sadness or anger) that can even lead the person to fall down.  The sleepiness can be severe and irresistible, so much though that the patient may fall asleep during routine daily activities such as driving, speaking and even when walking!  There are other more minor symptoms that include paralysis when waking up from sleep (which can also be seen in normals without narcolepsy) and hallucinations when falling asleep or when waking up.

     The cause of narcolepsy is thought to be an abnormality within the hypothalamus, which controls our sleep/wake cycles.  The condition is diagnosed by a sleep study.  The current treatments include stimulants to keep the patient more awake and medications to help the muscle tone.