help me figure this out...

[Chiaroscuro]

It's also possible, drifter god, that you're experiencing some type of anxiety attack. I'd talk to either your doctor or a psychologist and see what they think. I tend to get anxiety attacks-slash-restless legs syndrome at night where I can't stop shaking and feel unreasoning fear; sometimes it helps me to put more blankets on. The human mind is a strange thing...
The other thing I always get is (to use the words of Jim Davis) the "seconds-before-blissful-slumber-body-spasm."

[Darth Wong]

Now that I think of it, though I'm sure there's no simple causal relationship one way or the other, I wonder if there's a correlation between religious upbringing and persistence of nightmares or similar experiences. I could imagine a slight subconscious enhancement towards fearing those things when you're raised in a tradition that not only tells you that these beings are real, but will get you if you're not good enough.

As Turin points out, the religion may not cause the nightmares, but it can cause you to interpret them in a much more terrifying way that can really affect your life. And that might lead to more nightmares, not to mention social problems.

Imagine if you're an ignorant fundie medieval innkeeper, and a strangely clothed traveler has just come to stay at your inn. That night, you suffer through one of these horrible "shadow man" experiences. What do you think? Naturally, the strangely clothed traveler is an agent of the devil! I would hate to be that traveler in this hypothetical situation, because I suspect the townspeople would kill him in a really painful way.

[Turin]

Imagine if you're an ignorant fundie medieval innkeeper, and a strangely clothed traveler has just come to stay at your inn. That night, you suffer through one of these horrible "shadow man" experiences. What do you think? Naturally, the strangely clothed traveler is an agent of the devil! I would hate to be that traveler in this hypothetical situation, because I suspect the townspeople would kill him in a really painful way.

Yikes, I never even thought of that! And if you're that traveler, you've got no possible way of explaining yourself, as anything you can say at that point is only going to "prove" that you've been walking outside your body or other such mystical nonsense.

[anybody_mcc]

Christ, that sounds terrifying. I wonder why I've never had experiences like this. For that matter, I never have nightmares either.

Just reading those give me chills. The closest experience I've got was waking up after a dream where I ended up tripping into a pitfall. I lurched out of the bed with that feeling in your gut after you ride one of them falling amusement park rides.

Why don't you have nightmares?

Well , in my case I dont' have nightmares per se, because i love being afraid , so if I have frightening dream I am rather happy , not the other way around . But I always liked forests at night and such things, one of my favorite games was playing hide and seek at night in the forest. Maybe it is toxoplasmosis

One of my friends told me about sleep paralysis and I just cannot imagine this. It sounds awful , but it means nearly nothing to me because it is so alien to anything I have experienced. The strangest part is I would love those dreams because I know that for me it would be just interesting. On the other hand the feeling that the people having this nightmares have , that I would not like.

[Spin Echo]

I haven't seen any research on it, but if I had to guess, the "shadow man" phenomena in sleep paralysis is the result of mirror neurons. There was a recent article in The Economist (sorry, I only have the print version) that mentioned how test subjects that had their mirror neurons electrically stimulated experienced the sensation of a "shadow man", which was really an exterior projection of their own self-image. The human brain is fucking weird like that.

Was this article about how researchers found the part of the brain that is responsible for religious experiences? When the researchers would activate that portion of the brain using magnets, religious people would report having a religious experience. When they tried it on Richard Dawkins, he reported having an overwhelming feeling that there was someone in the room with him, even though there was not. It would be interesting to see if these areas of the brain were activated during the "shadowman" sleep paralysis episodes. Unfortunately doing fMRI on sleep research can be rather impractical.

I don't have nightmares, despite the fact I commonly have zombie dreams. They just don't bother me for some reason. When I'm sick and feverish, I will have a little short dream segment (varies each time as to what its about) that keeps repeating over and over again. It's not frightening, but rather tiring. I feel even more tired after that sort of sleep.

[ArmorPierce]

I get sleep paralysis mostly when I'm not getting enough sleep and am stressed out. Happened to me a lot in high school after moving to Jersey. New town, didn't no anyone, homesick, grades started to slip, which caused worrying about school, family had money problems, dysfunctional family which caused a stressful home environment, etc, etc, etc. Around this time I started having sleep paralysis a lot sometimes multiple times during at night after which I would I'd feel like I couldn't take it anymore and would just sit on my bed not wanting to go to sleep no more.

I found that the best way to deal with it was to not panic. I think just about every time it happened I realized that it was a dream but at first I would panic and that would cause the scary stuff to happen (you know, besides being all but paralyzed). I would start hearing, seeing, and feeling stuff, even being levitated off the ground by some super natural evil force and hurled and slamed across the room. The scary part is that this all felt very real. If I though about my breathing instead of letting it happen automatically, I would start having problem breathing too! I could barely make myself move my arm with great will power and with great difficulty. A way that I try to wake myself (actually a trick I picked up here I think) to attempt to snap my head to the side suddenly and quick.

I'm going to go through my post history to try to find my post about sleep paralysis experience.

[Seggybop]

Just reading those give me chills. The closest experience I've got was waking up after a dream where I ended up tripping into a pitfall. I lurched out of the bed with that feeling in your gut after you ride one of them falling amusement park rides.

Not sure if it's the same thing as you're describing, but whenever I get killed in a dream I wake up with a feeling like I've just been dropped onto the bed from above.

[Winston Blake]

It's also possible, drifter god, that you're experiencing some type of anxiety attack. I'd talk to either your doctor or a psychologist and see what they think. I tend to get anxiety attacks-slash-restless legs syndrome at night where I can't stop shaking and feel unreasoning fear; sometimes it helps me to put more blankets on. The human mind is a strange thing...
The other thing I always get is (to use the words of Jim Davis) the "seconds-before-blissful-slumber-body-spasm."

Technical term: hypnic jerk. Here's a neat list of hypnagogic phenomena besides sleep paralysis (and the associated 'waking nightmare' hallucinations):

Hypnagogic sensations

Hypnagogic sensations are vivid dream-like experiences that occur as one is falling asleep or waking up. Accompanying sleep paralysis can cause the sensations to be more frightening. The features of these sensations generally vary by individual, but some are more common to the experience than others:

Most common

* Vividness
* Impending doom
* Falling sensation
* Fear

Common

* Sensing a "presence" (often malevolent)
* Pressure/weight on body (especially the chest or back).
* A sensation of not being able to breathe
* Impending sense of doom/death

Fairly common

* Auditory sensations (often footsteps or indistinct voices, or pulsing noises). Auditory sensations which are described as noise instead of sensations of distinct or comprehensible sounds, are often described to be similar to auditory sensations caused by Nitrous Oxide by persons who have experienced both.
* Visual sensations such as lights, people or shadows moving around the room

Less common

* Floating sensations (often described as out-of-body experiences)
* Seamless transition into fully immersive lucid dreaming, also associated with out-of-body experiences
* Tactile sensations (such as a hand touching or grabbing)

Rare

* Vibration
* Involuntary movements (sometimes the feeling of sliding off the bed or even up walls).
* The feeling of being pulled in different directions

Looks like we have some people here who've had rather uncommon effects.

Some report that various factors increase the likelihood of both paralysis and hallucinations. These include: [2]

* Sleeping in a supine position (facing upwards)
* Irregular sleeping schedules; naps, sleeping in, sleep deprivation
* Increased stress
* Sudden environmental/lifestyle changes
* A lucid dream that immediately precedes the episode. Also conscious induction of sleep paralysis is a common technique to enter a state of lucid dreams, also known as WILD[1] .
* Artificial sleeping aids or antihistamines

So people who are pretty stable and secure in life probably won't be affected by sleep paralysis.

[Tasoth]

Sleep paralysis is down right frightening. The only episode I had of it, I was convinced beyond a shadow of a doubt a demon with a bag was ticking off the ways he was going to torture my family and that I was the root of it. I couldn't move, no matter how hard I tried and I was aware of everything around me. I actually woke up somewhere in my nth iteration of the Our Father that I drudged out of my mind from childhood. I only fell asleep because the fear fatigued me.

[Ariphaos]

As Turin points out, the religion may not cause the nightmares, but it can cause you to interpret them in a much more terrifying way that can really affect your life. And that might lead to more nightmares, not to mention social problems.

It's often attributed to the most terrifying visions of religious experiences. When you read about 'witnesses being overcome with fear' - each and every time, I'm almost certain it was such a terror. It's just how they saw it. Where I saw an alien and two shadows, they saw angels, or Jesus, or the virgin Mary.

Or elves, or oni - this goes across many cultural bounds after all.

Imagine if you're an ignorant fundie medieval innkeeper, and a strangely clothed traveler has just come to stay at your inn. That night, you suffer through one of these horrible "shadow man" experiences. What do you think? Naturally, the strangely clothed traveler is an agent of the devil! I would hate to be that traveler in this hypothetical situation, because I suspect the townspeople would kill him in a really painful way.

Honestly, I couldn't blame the innkeeper. I'm not fearless, but... facing death is a hell of a lot easier then sitting there, meeting what seems to be a malevolent entity standing there watching you prepared to do who knows what - flay you alive and put you back together, but that's not quite enough because you know that. You understand, and understanding gives you strength. It won't help your agony... but it helps your will.

These things are fear of the unknown, incarnate.

And when I saw a reasoned, valid explanation for what happened, and repeated it myself, I went from stalwart UFO believer to skeptic in a day. The dreams, when they came again, were still terrifying - but I knew them, and force of will could break them, and that's all I needed.

[Nieztchean Uber-Amoeba]

I've never had sleep paralysis per se, but I think my overly imaginative nature and noctophobia lead to fucking scary situations. I remember closing my eyes and holding them as tight as I could once in a dark room when I heard weird noises because if I woke up I would see whatever it was and that terrified me and maybe then it would know I saw it and it would do horrible things to me. Like the mysterious disappearances on the History channel. Like the spontaneous combustion on the Discovery Network. Like abductions on the Space channel.

I couldn't sleep for hours. And this thing happens to me like, all the time. I just remember so emotionally how I had to keep my eyes closed, and not find out what it was, and not run away, and not get up, and not move a fucking muscle. Because then I might see something. And it might see me.[/i]

[Turin]

Was this article about how researchers found the part of the brain that is responsible for religious experiences? When the researchers would activate that portion of the brain using magnets, religious people would report having a religious experience.

I know which study you're talking about, but this was different. The article in the Economist was referring to was in Nature, and I've found a summary here. You can find a link to the abstract of the paper in Nature, although the full text requires subscription.

Stimulation of a site on the brain's left hemisphere prompts the creepy feeling that somebody is close by.

The strange sensation that somebody is nearby when no one is actually present has been described by psychiatric and neurological patients, as well as by healthy subjects, but it is not understood how the illusion is triggered by the brain. Here we describe the repeated induction of this sensation in a patient who was undergoing presurgical evaluation for epilepsy treatment, as a result of focal electrical stimulation of the left temporoparietal junction: the illusory person closely 'shadowed' changes in the patient's body position and posture. These perceptions may have been due to a disturbance in the multisensory processing of body and self at the temporoparietal junction.

There's no mention of the mirror neurons issue here, but I had just read something in Scientific American/Mind on mirror neurons when I'd read this article a month or so ago, so maybe I was confusing the two.

Looks like we have some people here who've had rather uncommon effects.

True, but the wiki article is about hypnagogic sensations in general. If you look at some of the earlier posted articles on sleep paralysis, you'll see that CSP is fairly ordinary, but if I had to guess I would bet that few people really remember it vividly when it occurs. So I imagine there's going to be a selection bias for reporting of hallucinatory sleep paralysis when the subject comes up on a discussion board. With it being such an unpleasant experience, there's a certain comfort that comes in knowing that there's other people that have shared it and can really understand what it's like.

So people who are pretty stable and secure in life probably won't be affected by sleep paralysis.

Not to nitpick, but they're "less likely" not "probably won't." As reported by several folks here, stress seems to increase frequency of experiences of HSP. But I've managed to get to a reasonably happy and normal state in my life but I still occasionally experience both CSP and (even less frequently) HSP. I'm sure there are plenty of really unstable people who've never experienced it, too. The hereditary aspect would indicate that there's some innate feature of some people's brains that make them more susceptible to sleep paralysis, that might not have anything to do with their psychological state.