FWIW, I'm on 400mg of Lamictal as well and it doesn't stop my mood swings. In fact, it hardly stabilizes my mood, if at all. HOWEVER, the med's gotten rid of my chronic extreme agitation, which is why I keep taking it.

I don't know how to answer your AP question. The problem is that bipolar changes over the course of time. You may be stable for 5 years, then suddenly go into rapid cycling without realizing it, or vice versa.