my bf just got heavy into astral projection and meditation and he says it's seriously affected his dreams. He used to have a sleeping problem where though he would be unconcious for 12 hours at a time, he would never get enough rest because he would be trapped in rem the whole time. Anyway since he's started all this he has noticed that the people in his dreams are often people he doesn't know, has never seen, or heard of. So he thinks the dreams are just another plane of existance.

Ever wake up in a dream? Your dreaming and you suddenly realize that your dreaming? He does it all the time.