In my opinion the term "sleep paralysis" is a title given to what they (science) don't understand, or are afraid to acknowledge, ie. the beginnings of possible astral projection. It's like having one foot in the door. Interesting how science believes it has all the answers and actually attempts to curb a naturally occurring phenomena.
Ever wonder why the ancients were able to travel to wonderful and mystical places, come back and tell, or write about them?
A lot of these mystical adventures took place while the subject was sleeping, and were called visions. Because they were so lucid they knew the difference between mere dreams and actual astral journeys, and of course lacked medication to alleviate what modern science deems "a disorder".
Don't let the artificial term "sleep paralysis" rob you of the magic of astral projection. Their (science) job is to keep your feet planted securely in what they see as reality, and in modern times anything deemed to be outside of "their" reality is considered abnormal, and must be labeled with a negative term. I say don't let fear be your guide, and try it.
I've astral projected many times and although extremely frightening at first, it's an experience you'll cherish for the rest of your life.
I've found that during what is termed "astral projection" you are subject to neither time nor space, and are free to travel in an extremely lucid and conscious state, either forward, or backward in time, and to places that are way beyond anything anyone could possibly imagine, or dream of. Study and try some of the techniques you'll find in other forums here at UM dealing with astral projection, and give it a go. Peace