I used to have a lot of nightmares although I think it was PTSD and not the meds. Now that I've completed extensive PTSD therapy I have nightmares mostly when manic, just when I get that little burst of sleep that lets you know you can live through tomorrow. But I had a sleep study done to see if my asthma was also causing sleep apnea and found out that I get very, very little REM sleep (20% of normal I think) so any dreams that I remember are pretty rare and while I do dream it's not nearly as much as most people. Which is why I'm tired all the time, in part...

When it is worst is when I have a big list of things to accomplish and my brain wants to use that "slow time" to solve all of them and that keeps me awake.