I was doing fine on Seroquel XR at a low dose, 150mg (I think?), when I started getting manic. My pdoc increased the dose to 250mg and I became extremely suicidal. It gave me literally the worst depression I've ever experienced. I thought my feelings of depression could be associated with me "crashing," but that didn't seem right... because I was fine for a few days (no mania; completely stable) and then all of a sudden I became depressed 4 days after increasing the dose. So I just plain asked my pdoc to go off the med because I felt that it made me depressed, and I also didn't like that it made me too sleepy. And sure enough, when I went off the med, the depression lifted within a day or so and I felt fine.

I didn't have any weight gain or anything like that (or maybe it was minimal? can't remember). It was just the severe depression that bothered me.