Suppose (for reductio) that a person is an appropriately related series of person slices. And say that person slices are appropriately related if and only if they are psychologically continuous with one another. Fine. Let it be noted that some people with schizophrenia are comprised by series of person slices which lack this psychological continuity. This entails that these schizophrenics are not persons. But they are. Therefore, we must reject the view that a person is an appropriately related set of person slices. And the four-dimensionalist view of persons cannot be correct.