Distribution and type of switch between antipsychotics made in 52-weeks prior to hospital admission. Titrated switches were defined as any switch involving either a gradual reduction in dose of the old antipsychotic or a gradual increase in the new antipsychotic within 3 weeks of starting the second drug. Immediate switches were made with no overlap between the two drugs, and no titration. Gap switches involved the termination of one medication with a period of less than three weeks where there were no records of antipsychotic prescriptions prior to starting a different antipsychotic. Overlapped switches involved the two drugs being prescribed concurrently for a period of less than three week with no reduction of dose in the initial antipsychotic, nor a gradual increase in dose in the second drug.