, it seems likely that some process kills the orexin neurons, resulting in narcolepsy with cataplexy.
Thus far, the cause of narcolepsy without cataplexy is less clear. Researchers have examined the brains of only a few people with this type of narcolepsy, and these seem to have only a moderate loss of the orexin neurons.19 orexin-1 levels in spinal fluid are usually normal, although about 30% of these individuals have low or undetectable levels.18, 20 Among these people with low orexin, about one-third may develop cataplexy years later,20 suggesting that there may be some ongoing injury to the orexin neurons. Thus, narcolepsy without cataplexy may be caused by a less severe injury to the orexin neurons, but because so little is known about this form of narcolepsy, it remains possible that it has an entirely different cause.
See Developing New Treatments for the latest findings on potential new treatments for narcolepsy.
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