Hopefully your doctor will have some additional ideas. They will know better than me.

Seroquel (I take Seroquel XR) is actually very helpful for all types of my episodes. I am currently on 500 mg and take up to 600 mg usually. I'm not sure what you mean by not being able to take more than 200 mg. For many, more than 200 mg is more helpful. According to stated average doses on most drug websites, 300 mg is the usual dose for bipolar depression and 400 to 800 mg for bipolar mania or mixed states. Of course that can be higher or lower for some people. The body adjusts for most people. If your doctor suggests an increase I wouldn't dread it. If after some time a higher dose did more harm than good that's another story. Higher doses don't necessarily sedate more than lower, but I've read (and experienced) that higher doses of Seroquel work more as a moodstabilizer than lower doses. When I've needed a Seroquel XR dose change, changes as low as 50 mg up or down (or more often 100 mg up or down) did make a clear difference for me.