Moyamoya disease in a 12-year-old Caucasian boy presenting with acute transient psychosis.

This paper reports the case of a 12-year-old boy who presented with an acute transient psychosis. Investigations revealed Moyamoya disease with occlusion of the left middle cerebral artery. There was no previous history of transient ischaemic attacks, no history of psychiatric disease, no family history of psychosis and no history of illicit drug use. Although no previous cases of Moyamoya disease with psychosis as the sole presenting feature have been described, we suggest the possibility of a causal link.