To the Editor: Topiramate, an antiepileptic medication, is often used as an adjunctive mood stabilizer for patients with bipolar disorder +(1). Potential weight loss makes this medication appealing; however, depression is another reported side effect +(2). We report on three patients with bipolar disorder in which topiramate may have exacerbated depression. Topiramate was prescribed in lieu of higher doses of the patients’ current mood stabilizers because of concerns about weight gain.

We report on these patients to highlight a possible relationship between topiramate and substantial depression in patients with bipolar disorder. Symptoms of depression began or increased within 1 week of topiramate treatment or with titration to 50 mg/day. Each of the patients experienced significant relief from depression 1 to 2 weeks after discontinuation of topiramate. The close association with onset of the most severe depression these patients had ever experienced is notable. However, although no new medications had been initiated in the previous 3 months in any of these cases, all of the patients had a diagnosis of bipolar disorder, so the onset of depression could have been coincidental. Their depression may also have been due to a synergistic interaction between topiramate and their other medications. These symptoms of depression correlate with the neurology literature +(2, +3), in which psychiatric disorders are noted to occur with topiramate therapy. Although topiramate has been shown to be effective in mood stabilization, physicians prescribing it should be aware that serious depression might be an adverse effect. This observation merits further research.