Many of the medications that are utilized for the treatment of bipolar disorder have weight gain as a side effect. Valproate (Henry et al., 2003), several of the atypical neuroleptics (Wirshing et al., 1999), and lithium (Atmaca et al., 2002) have all been shown to increase weight in patients. Psychotropic-induced weight gain not only leads to problems in compliance (Aronne and Segal, 2003), however obesity is associated with a broad array of health problems and risks (Allison et al., 1999).

The purpose of this study by Sachs and colleagues was to assess the effect of lamotrigine on weight in patients with bipolar I disorder. 588 patients from 2 long-term maintenance studies were included in the analysis. Patients were treated with lamotrigine (N=230), lithium (N=167), or placebo (N=191). At the end of one year lamotrigine-treated patients had a mild weight loss (-1.2 kg) compared to a minimal placebo-associated weight increase (+0.2 kg). The lithium-treated cohort experienced a weight gain of 2.2 kg.

The findings from this study are consistent with studies of lamotrigine in patients with epilepsy. Devinsky and associates (2000) reviewed 32 studies in seizure-disorder patients and found that lamotrigine treatment resulted in a negligible weight gain. Thus, in addition to the effectiveness of lamotrigine in the stabilization of mood, its favorable weight side effect profile should be considered in the choice of this agent.