More vivid dreams is common, and for some people the dreams are nightmares. (Not for me, though.)
I did have more vivid and "weirder" dreams, especially in the morning (perhaps memory bias), and a handful of them were quite disturbing, far from my norm. But, this lessened after a couple of weeks of off and on use.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.