Recurrent Psychotic Episodes with a Near-monthly Cycle.

A 12-year-old girl presented to the mental health service for an abrupt onset of mental changes characterised by hearing voices and being paranoid. She appeared preoccupied and her mood was labile. There was no family history of mental illness, and no organic causes were identified. These symptoms subsided spontaneously in a week. However, she experienced 3 other similar psychotic episodes afterwards which happened in a near-monthly cycle. Her level of functioning was normal between these episodes. Throughout the course of the illness, it was noted that these mental state changes might be related to the menstrual cycle. In this case we discuss the recurrent periodic psychoses in adolescents and the important differential diagnoses to be considered, including menstrual psychosis, a rare and less well-understood clinical entity.