You probably already know lamotrigine (
Lamictal) works better for the depression
side more than the manic
side. So this is why I think the lithium/lamotrigine combo is good, because you get the antimanic effect (which you don't get with lamotrigine) and the antidepressant effect (which, according to some MDs, you don't neccessarily get with lithium, and without the risk of going manic).