I have used this drug for BP1 for five years, and it's been the best drug for controlling mood swings that I've used, especially and unexpectedly establishing a "floor" that prevents/lessens depression periods I'd formerly experienced more frequently and strongly.
Lamictal for me does well to moderate mood swings, esp. now that I take 300 mg combined with 600 mg of Trileptal, but the latter, also developed as an anti-seizure med, makes me groggy and spaced-out.