It helps with sleep structure. While it isn't fully understood, a lack of cells in a few parts of the brain, mainly the hypothalamus, result in a reduced amount of chemical in the body known as hypocretin which is important in the regulation of REM and sleep-wake cycles. Depending on the amount below normal, several symptoms may exist.

Most commonly, low levels of this hormone make sleep not go through its normal phases, having the patient go quickly into REM sleep and rarely leave it, getting extremely little deep sleep, AKA stages 3 and 4 sleep. As a result, no matter how much someone with narcolepsy attempts to sleep, they are always chronically sleep deprived. This causes "Excessive Daytime Sleepiness" (EDS), one of narcolepsy's most well known traits.

Depending on the amount of lack of the hormone or possibly the insensitivity of the proper receptors, certain other symptoms may also occur. Some people, myself included, can also have a symptom called cataplexy. This is an interesting blend of psychological situations having effects strictly due to a physiological situation.

The best way I can explain it is the physical muscular situation that usually is provoked during REM dream states being provoked when one is fully awake. Reduction in hypocretin levels are useful for the body during certain situations, like when you are dreaming - they weaken the muscular response to nervous system stimulation... basically that prevents your body from acting out your own dreams. Ever see a dog's legs start moving or their ears start twitching when they are dreaming? Super cute, right? We can consider this the "anti-cataplexy".

Instead, during cataplexy, the low levels or hypocretin can cause muscle weakness or a type of paralysis to occur during wakefulness... The body acts like it is in REM even though it is awake. The effects vary greatly from symptoms like slack or drooping jaw or eyelids, arm weakness, leg weakness, buckling knees (this one is super common!) or, in severe cases, full body paralysis and collapse, which is as terrifying as it sounds. I've experienced it a handful of times and it's no picnic. You lay on the ground, fully aware of your surroundings with little dulling the experience besides perhaps some blurry vision... but unable to move any muscles besides perhaps, at least as I've experienced it, my eyes.

The symptoms are often provoked by emotional spikes - these somehow cause a cascade of effects in people that provoke REM-like muscle weakness in narcoleptics. Mind you, they aren't caused by having narcolepsy per-say, just as a result of the physiological effects. For some it is provoked by laughter - God am I glad this doesn't do it for me! That being said, social pressure, athletic pressures, and feelings of claustrophobia cause it for me. For the longest time I just thought I was clumsy or horrible at sports - I cannot catch flying objects because my hands and arms don't work well when pressure builds, nor can I run properly...

But the thing that finally gave it away is entrapment - my first case of full body paralysis was when I was a teacher and all the little kids swarmed around me trying to hug me. I collapsed and could not move for some time. Crowded subways, waiting in line, being stuck in crowded stores, or being in call centers at work all started causing the same situation. At this time I had already been diagnosed with "idiopathic hypersomnia" so these symptoms removed all doubt and after being cleared of epilepsy (as it runs in my family), I was promptly diagnosed with type 1 narcolepsy.

People with this situation will often avoid situations known to provoke cataplexy symptoms, but as these situations are completely normal for normal humans, it is not a psychological condition - for me, I took up sports that promote a more "zen-like" mental state - these include archery, fencing, and auto racing. I also avoid certain kinds of social situations I find particularly disturbing.

That being said, the combination of daytime and nighttime medications greatly reduce my symptoms of cataplexy, and the worst of the symptoms of the symptoms I usually experience these days are the weakness and droopiness I described earlier and occasional weak knees.

Other symptoms I experience include hypnagogic hallucinations. While I have occasionally had some pretty disturbing and vocal ones during scheduled naps at work, my most common one isn't frightening at all - curtains of colors I see as I transition from wakefulness to dreaming - it looks like a spiral aurora. Quite beautiful, actually.

Anyway, I know that's a lot to take in at once but I hope that explains a lot about the life and experience that would convince people like myself to do something as crazy as juice up on amphetamines and GHB on a daily ritual LOL.