Antidepressant medication and electroconvulsive therapy stabilize mood symptoms and increase hippocampal neurogenesis. We examined whether lamotrigine, suggested to give rise to mood-stabilizing and antidepressant effects in addition to its antiepileptic properties, also increases the number of newborn cells inrat hippocampus. Rats (on day P21) received lamotrigine, valproate, or saline intraperitoneally once dailyfor 7 days. All animals received four intraperitoneal injections of bromodeoxyuridine (BrdU) on day P28 andwere sacrificed the next day. Quantification of BrdU-labeled cells in the granule cell layer of the dentate gyrus showed an increased number of newborn cells in rats receiving lamotrigine (42.6±3.5 cells/slice) compared with valproate (31.6±2.8) and controls (32.2±3.1; P