Can schizophrenia-like disorders beginning in late life tell us anything about early life onset schizophrenia?

Arguments about the exact definition of the schizophrenic syndrome have persisted for over a century. These may not be resolved until biological markers are discovered. This article argues that the heterogeneity of the schizophrenic syndrome contributes to these disagreements and that one fruitful research strategy is to use this heterogeneity to our advantage. That is, we should be looking for similarities and differences among cases, identifying biological and social markers for both the similarities and differences, and using these to develop testable models of brain structure and function. Late-onset cases of schizophrenia disorder share enough similarities with early-life onset cases that they should not be overlooked as research subjects.