I used to find Seroquel/Quetiapine worked amazingly well for me. Once my dose was worked out and I was switched to the extended release variant. I think I had around 6 years of mostly great mood and was very focused and goal oriented for just about every hour I could wring out of the day. It was like I was mostly mildly manic and it was wonderful, albeit with some minor depression creeping in around autumn/winter, but they were extremely mild.
I finally had a more prolonged episode of depression after those 6 years, but within 6-8 months it lifted again and I was more or less back to normal.
Unfortunately for me, something seems to have changed around the middle of 2017 when I started to get anxiety and more severe depression, coupled with some horrible side effects and other physical symptoms.
I would say I got almost 9-10 years of recovery, or some version of recovery while on seroquel at 300mg extended release. It used to sedate me on an evening, so if I needed sleep it was basically guaranteed I would get it. The way I see it, this med reversed the mood cycles and made depressions trivial. High mood never got out of control so I was just a whirlwind of activity without the head full of rushing thoughts and noise and wonky ideas.
Sadly now it doesn't have that affect on me at all. I take it still as I fear the alternative may be much worse than the pain, restless legs, the lack of energy and brain fog.
The other thing I should mention is that the problem may not actually be the medication, it could be that some issues I have with my blood and body chemistry might be interacting in an unusual way with the seroquel.
I suppose I will find out once the doctors figure out what's causing these issues. I hope that perhaps I will return to my happy hyperactive, ambitious, focused self if they fix the problem.