Seroquel and I have a long history.....

I've been on both the regular and XR versions, but mainly the regular, since XR makes me feel especially sleepy and sometimes dizzy during the day.

As far as regular (ER) Seroquel goes, I've been on all different doses. When I first started years ago, I started on 50 mg. Eventually I stepped up to 100, 200, 300, etc. (eventually hitting 800 as time went on, when my newer Psychiatrist determined it would be necessary since at the time, I was having an acute mixed manic episode).

At 50-100: These doses were very sedating in the beginning. I slept so easy. It would knock me out.
200 mg- I started to feel immune to the 50-100 mg doses for sleep, so this dose started to be more effective. This is when I began to notice it also had more of an affect on lowering anxiety a bit.
300-400 mg: The mood stabilization effects started to really kick in. Especially at 400, which is considered a "maintenance dose" for preventing Bipolar depression and mania. Right now, this is the dose range I am on, since it is helping prevent me from going into such a severe episode, although I still have my issues. The downside: sometimes I feel lightheaded in the morning still. It helps me sleep very well. Actually, I can't sleep without Seroquel, but it starts to feel quite powerful in a way that sometimes makes me feel kind of nervous from time to time. It does help anxiety during the day.

600 mg +: I needed time getting used to 600 mg for sure. At first, I'd get lightheaded in the morning. There were days that I didn't think I would make it to work due to feeling dizzy driving. I would need to sit down, since my blood pressure would drop a little bit. It did wonders for mood stabilization and getting out of swings between mania and depression, but I'm glad I didn't stay on this dose long-term. I would get hand twitching, especially when I would do something simple, like pick up a pencil. I was hardly able to stay away from sweets and gained a little bit of weight, but not noticeably so to others. Sometimes it felt scary-sedating. I am glad I am off of this dose, but would consider going back to it short-term, if I enter a severe episode in the future.

I just stepped down to 300 mg for the first time in years and have decided I will never ask to lower it from this point on, but I will only increase it , if I feel it's absolutely needed. It is the only medication that helps me sleep, unfortunately. If I don't sleep, mania will set in quickly. It does help reduce some anxiety though. Tapering down was a bit tough. Angry outbursts came out a lot, interfering with some of my relationships temporarily...but I'm adjusting (I think).