There can not be many people who have not seen the film "Moby Dick", either in its original 1956 version with Gregory Peck, or the more recent 1998 television adaptation with Patrick Stewart. I'm sure too that many people will have read the book itself, written by Herman Melville way back in 1851. What you probably will not remember however is one particular passage from the book in which the narrator, Ishmael, says:
"For what seemed ages piled on ages, I lay there, frozen with the most awful fears, not daring to drag away my hand; yet ever thinking that if I could but stir in one single inch, the horrid spell would be broken. I knew not how this consciousness at last glided away from me; but waking in the morning, I shudderingly remembered it all, and for days and weeks and months afterwards I lost myself in confounding attempts to explain the mystery. "
Although sleep paralysis would not be described by the American neurologist Weir Mitchell for another 25 years, this gives us a vivid account of a condition that has been around since the dawn of time.
Sleep paralysis is one of a number of unwanted events that occur during sleep (including sleep walking, nightmares, night terrors and restless legs syndrome) and about half of us will experience at least one episode of sleep paralysis during our lifetime. For many narcolepsy sufferers, however, sleep paralysis can be a common occurrence and, if accompanied by hallucinations (another frequent symptom of narcolepsy), it can be a particularly frightening, or even terrifying, experience.
Sleep paralysis very rarely presents any real danger to the sufferer. Nevertheless, it is an experience that most of us could live without and one for which we would dearly love to have a cure. Unfortunately, however, there is no cure at present, but, there is light at the end of the tunnel.
For some time now it has been known that human leukocyte antigen, or HLA, (a protein found on the surface of white blood cells and forming part of the body's natural defense or immune system) has played a part in causing narcolepsy. What has not been understood though is just what role this protein has played. In two separate studies carried out in Texas and California in 2000 however the true role of HLA emerged and this is now being confirmed in a series of further studies, the most recent of which (June 2005) comes from the University of California, Los Angeles (UCLA).
It appears that narcolepsy is caused by the lack of a particular chemical called hypocretin or orexin that is normally produced by the brain and plays a key role in maintaining a normal sleep pattern. In the case of narcolepsy sufferers this chemical is missing because of the presence of an autoimmune disease. In other words, the body's immune system, instead of attacking foreign invaders, attacks healthy cells (in this case hypocretin or orexin molecules) and destroys them.
So what does all this mean for narcolepsy sufferers?
Well, it certainly does not mean that a cure will appear tomorrow, but it does mean that scientists now know how to cure the condition. On the one hand they can look at methods of preventing the body's immune system from attacking hypocretin or orexin molecules and, on the other hand, they can develop a method of replacing the lost molecules.
This will of course require further research and clinical trials and will take some years. In the meantime, sufferers will need to stick with their current recognized drug treatments and continue to pursue a policy of sound sleep hygiene and behavioral management. But the knowledge that scientists have now pinpointed the cause of narcolepsy and that a cure is at last in the pipeline should act as very good encouragement for anybody living with narcolepsy today.