Lamictal is not associated with weight gain.

Lamictal is not associated with increases in body weight. In an analysis of 638 patients randomized to 18 months of therapy for the long-term management of bipolar disorder, weight gain for patients treated with Lamictal was similar to that of patients treated with placebo. In trials studying other medications for the treatment of bipolar disorder, weight gain has been consistently observed – especially with olanzapine and lithium.