The anticonvulsants carbamazepine (CBZ) and valproate (VPA) have efficacy in the treatment of mood disorders, suggesting that other anticonvulsants with related mechanisms of action may have similar utility. Additional treatments are sorely needed because many patients with recurrent affective disorder have symptoms refractory to treatment with conventional agents, including lithium, carbamazepine, and valproate. This refractory group is the major focus of our investigative efforts on 3-west in the Section of Psychobiology, NIMH. Moreover, establishing differential clinical and biological predictors of response has become increasingly important both to rapid allocation of appropriate treatment and as they may supply insight into the pathophysiology of the mood disorders and their subtypes.