The use of anticonvulsants as treatments for bipolar affective disorder is growing, and despite relatively scant data, anticonvulsants have become widely accepted as adjuncts to lithium therapy, particularly as alternatives to neuroleptics. Although most of the research work to date has involved carbamazepine, improvement in bipolar symptoms with clonazepam has been exhibited in controlled studies and case reports. The author summarizes studies done by the Bipolar Research Group of the Clinical Psychopharmacology Unit at Massachusetts General Hospital. The data thus far indicate that clonazepam can be added to the treatment regimen of bipolar patients and apparently reduces cycle frequency; many patients using neuroleptics and lithium can be switched to lithium and clonazepam without suffering acute relapse; and clonazepam may be associated with fewer depressive recurrences than neuroleptic treatment.