Recent research has discovered that narcolepsy is a genetically controlled autoimmune disease. Individuals with the gene HLA-DRz/DQI have a very high risk that their immune system will attack a
part of the brain called the hypothalamus. It is in this brain region that an important neuropeptide called hypocretin is made.
Hypocretin is a very important neuropeptide for maintaining alert wakefulness. If the cells in the
hypothalamus that produce it are damaged or destroyed, narcolepsy occurs.
This condition is characterized by a tendency to fall asleep inappropriately during the day. Other unusual symptoms can also occur, such as cataplexy (sudden loss of muscle tone); sleep paralysis (awakening to find your body paralyzed except for breathing); hypnogogic hallucinations (seeing hallucinations just as you’re falling asleep), and what may seem like absent-minded behaviors (such as driving past your exit on the interstate or putting clothing in the refrigerator).
The lack of alerting effects of hypocretin allow non-REM sleep and/or REM sleep to intrude into wakeful times; hence, the unusual symptoms.
Treating this condition can be very helpful but – as in all medical illnesses – it requires an accurate diagnosis. This is probably best accomplished by a sleep doctor. Unlike sleep apnea, it doesn’t respond to CPAP treatment. The two main treatments are daytime stimulants and methylphenidate, and REMsuppressants such as protriptyline.