I was on seroquel and I had horrible reactions to it and had to be taken off of it. It left me scared - arms, chest, and face... And I had nightmares and would wake up, afraid to fall back to sleep. Since I've been on Abilify I have only had a very few nightmares (due to thinking about where I use to work...). I sleep great now - in fact I sleep hard and feel rested when I get up in the mornings. It has caused me to sleep longer than I use to sleep - but I have to take two benadryl with my abilify at night along with one Xanax - otherwise I don't sleep at all for days... But I would definately tell your doctor about your nightmares. Heres wishing you the best and a great nights sleep!!