That's what scares me, too. I use lamotrigine, and it's fairly new as well. At this point it seems like a good bet, with relatively few side effects, but there might be unknown long-term effects. I don't want any surprises in the long run... I guess that's the benefit of meds like lithium. They may have more side effects, but at least they've been studied for a long time so the effects are well known.