Although associations between antipsychotic use and neuropsychological impairment in bipolar I disorder have been observed, there is a lack of studies comparing the effects of specific agents used in this population. We compared performance between patients receiving maintenance treatment with mood stabilizer monotherapy (n=15), adjunctive risperidone (n=15) or quetiapine (n=17), and a group of demographically matched healthy controls (n=28) on tests of executive function (working memory, set shifting, and inhibition) and verbal learning. Despite having a similar clinical profile, patients being treated with risperidone showed significantly impaired working memory, set-shifting, and verbal learning (P