The reason I asked was because I've had it both ways.
I have Bipolar II, which is commonly treated with Lithium. One of the side effects of Lithium is short term memory loss. Combine that with weapons grade ADHD and you end up with a stretch of time you barely remember. For me, that stretch was 2 years long.
During those two years, I remember being generally happier -- and so do the people who were around me at the time... but I don't feel like it was worth it.