I'm just the opposite, when I'm down or stressed, I eat,cause of hunger pangs, that I usually do not feel that strongly when I'm feeling alright.
I take the blame for my weight gain(s),plus being menopausal doesn't help one's weight (figure), sooooooooo I will not blame it on the Lamictal.
I do know that Depakote DOES cause weight gain, when I first was DXed that is was the first med doc's tried, it had negative effects,we went on to try some others,and eventually, ended up with Lamictal, I take 200mg's per day.
Lots of luck with this, keep the faith.