Lamictal is an anticonvulsant medication that can be used to treat seizure disorders and as a mood stabilizer in bipolar disorders. In the original clinical trials, 5% of adults with epilepsy lost weight while taking Lamictal, while between 1 and 5% of patients with Bipolar I disorder gained weight. The amount of weight gained or lost is not listed.
A study comparing the effects on weight of Lamictal, lithium, and a placebo found that some patients receiving Lamictal gained weight, some lost weight, and most remained at about the same weight -- but the weight changes weren't significant compared to the placebo group. Obese patients taking Lamictal lost an average of four pounds, while non-obese patients' weight remained essentially the same.
Another study that looked specifically at Lamictal for possible treatment of obesity found that the drug definitely caused a decrease in BMI compared to placebo. Thus, researchers feel confident placing Lamictal in the "weight neutral" category.
Sources:
Bowden, Charles, MD, et al. Impact of Lamotrigine and Lithium on Weight in Obese and Nonobese Patients With Bipolar I Disorder. American Journal of Psychiatry. 163.7 (2006): 1199-1201. Web. 18 Feb 2011.
Meredith, CH. A single-center, double-blind, placebo-controlled evaluation of lamotrigine in the treatment of obesity in adults. Journal of Clinical Psychiatry (via PubMed) 67.2 (2006): 258-62. Web. 18 Feb 2011
