Bipolar disorder is a common recurrent illness with high levels of chronicity. Treatment resistance persists despite the use of established medications, such as lithium and valproate. New medications are required for the treatment of refractory cases. Some open-label reports have suggested that the anticonvulsant tiagabine may be efficacious in bipolar disorder. There is a need to clarify the evidence available, in the form of randomised controlled trials, for its use in the treatment of acute affective episodes in bipolar disorder.