system
Given the following post, respond as if you're commenting on Reddit:
human
What is the data on medical marijuana messing with REM sleep?

I saw a bunch of studies and assertions that it ruins REM sleep. But I also saw stuff that says it's a miracle for sleep and anxiety and nightmares. These things don't seem to coalesce into one pattern; if it helps with anxiety, then it can't also not let you get real rest, becuase over time you would get worse anxiety from not being able to sleep. Bad sleep=more anxiety. Ditto nightmares, if you can't get real rest, then you get more nightmares. 

So what's going on? Is the data conflicting, does it matter who's being studied and why they're taking the drug, does it matter what particular type of thing they're taking, what ingestion method?
gpt
I can't answer all of it, but one of the main reasons cannabis is looked at as a possible treatment for things like PTSD/nightmares/night terrors/REM sleep behavior disorders is specifically *because* it inhibits REM sleep - no REM sleep means no nightmares/acting out dreams in real life/etc. It's not that the data is conflicted there, but instead that these studies haven't been looking at cannabis as the solution in the same way you think they are (improving sleep to reduce nightmares) and instead are taking a different route that takes advantage of a normal effect of cannabis (using it to suppress REM sleep and dreaming altogether to reduce nightmares) with the side-effect of somewhat lower-quality sleep.