To start searching for clinical stuff just google nightmares sleep apnea
http://www.ncbi.nlm.nih.gov/pubmed/17061140
http://www.medicinenet.com/script/main/ ... key=171651
Post a poll on this website asking how many had nightmare/scary dreams/death themed dreams before they started cpap and how many had the nightmare dreams once they had successfully adapted to cpap therapy.
If I use the cpap and its working good I don't get any bad dreams. Heck I don't remember dreams. Why cause I don't wake up while in REM sleep. When you wake and can remember the dream it will progress from something nice or harmless to something that has a death theme. Death themed dreams will be about vampires, zombies, getting shot, getting stabbed, getting beaten, electrocuted, drowning, being choked or sufficated. You may be being chased or running or fighting. You will also dream about people that are dead and that you knew. The whole point of the dream being scary is to eject you out of sleep. If you stay in a dream where you are not breathing, then the dream can get vivid. When I say vivid the imagery is so crystal clear its like seeing with your eyes closed. Usually the imagery may be cloudy when you remember it.
I have noticed that there are articles about soldiers that have PTSD and are being treated with cpap and it reduces the bad dreams. If a soldier saw bad things like his friends being killed and blown up and the death of unknown people where bodies are laying around. This is the very death themes that the mind will goto when O2 depletion occurs in sleep. Eliminate O2 depletion and you stop the jump to death themes to wake a person up. Does the person stil think/dream about bad shit that happened. Most likely. If they don't wake up they won't remember it. It just gets processed or what ever happens to memories in sleep. Since they are pushing the psych drugs on soldiers now, it hard to tell what all happens. They go off the psych drugs and all those bad memories may be unleashed. Suicides for soldiers once they are home are higher than battle casualties. This maybe how the military gets rid of people that they don't keep on a short leash on. You work for the govt and they keep you supplied with psych meds. You leave the govt and they put you on some other drug or no drugs at all and you go ape shit and suicidal.