For the years I've been taking it, it has entirely prevented mania though I don't know about depression since I take other things for that. The only side effect I had was akathisia and propranolol takes care of that completely. It doesn't make me sleepy. You have to take 350 calories with it which can be inconvenient (Doctors don't always know this; I can't imagine why--it's prominent on the instruction sheet.)

I will keep taking it as long as my insurance keeps paying for it. I had to fight with them last time.