This article gives an overview of the periodic catatonia syndrome, a concept first described by Kraepelin in 1908. A case history is given of a man who was followed from 1949 until his death in 1980. The typical pattern of periodic catatonia disappeared after neuroleptic drug treatment. Subsequently, there have been occasional reports of this unusual syndrome, but it is often assumed (wrongly) that it forms part of a manic-depressive psychosis.