hi. different people react to lamictal (or any other psych drug) differently. 100mgs helps my low moods w/o causing as many problems as antidepressants did (for me).

I have a friend who had some difficulties on 400mgs. The problems went away once the dose was reduced a bit. Maybe a dosage reduction is in order?

Lamictal is one of the safer, easier to tolerate drugs used for mood swings. Perhaps you should talk to your doctor about another option, or maybe consider non-drug treatments?