A woman with recurrent acute confusion: a case of cycloid psychosis.

A woman 46 years old presented with recurrent, brief, sudden-onset episodes of confusion, aimless motor overactivity and lability of mood, from which she recovered completely. She was admitted on each occasion to a medical unit with a provisional diagnosis of organic mental disorder and thoroughly examined. No organic etiology was identified. This patient meets the criteria for cycloid psychosis. The implications for diagnosis, investigations and management are discussed.