For the past few years I've been taking advantage of my REM cycle to nap efficiently (I've figured out the duration to within a few minutes). I have memorable nightmares (so they can't be night terrors) related to my PTSD. I was wondering if I could disrupt my sleep before I slip into REM in order to prevent dreaming. I know Dement did a study on REM deprivation, which showed that people who have been deprived tend to compensate by taking a larger percentage of sleeping time for this stage. But as far as I know, none of his subjects had any truly adverse reactions. Thoughts?