My grandmother has been on Lithium for a long time. Our family doesn't really talk about it, but she has lived a stable, happy life. She still has episodes that have led her to the hospital for re-evaluations (3 in the last 10 years), but they re-adjust her meds and she's back to her normal self.
I was put on it shortly after my diagnosis in college because of her sucess on it. I also had your same concerns, but decided that being happy & stable was more important to the what-ifs. As it turned out, it doubled my crying. I didn't want to get out of bed and withdrew from my friends. Needless, Lithium wasn't for me.
Mood stablizers effect everyone differently. You just never know until you're able to make the decsion to try it or not. Good Luck with your choice!