Wednesday, while I was an active JW, I had several experiences that I chalked up to "demons". These incidents had nothing to do with sleep paralysis, and they were truly disturbing at the time.
Since I have become inactive, however, and come to appreciate life without fear of being destroyed in an imminent cataclysm, there have been no further negative experiences.
At this point in time, I'm not really sure if God is, in fact, an actual entity, or if what we perceive as "God" is simply a postive force, or energy, into which we can tap. If this is so, then there is most likely an equivalent negative force, which is perceived as demonic. JWs tend to focus in on this negative force and would, therefore, have more experiences of the negative kind.
This is just a theory, and I have no idea if it is, in fact, correct, but it does explain a lot of things for me.