tal changes, but show divergence in structural deficits in other areas such as the thalamus, hippocampus, or cerebellum. Altogether, these studies demonstrate that brain structure per se is not a uniform endophenotype, but rather a combination of regional deficits highly heterogeneous in both meeting endophenotype criteria as well as in their distribution within the disease category. Clinical Heterogeneity and Subtypes of Schizophrenia Kraepelin's original concept of dementia praecox originates

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... in a synthesis of the previously separately classified disorders of hebephrenia, catatonia, and dementia paranoides. Hence, although the 'Kraepelinian dichotomy' separating schizophrenia from manic-depressive illness provides a delineation of psychotic disorders in two large groups, it also relies on grouping together entities previously conceived of as distinct. Similarly, Eugen Bleuler's conception of the 'group of schizophrenias' acknowledges the clinical (and putatively etiological) heterogeneity of schizophrenia. However, there has been only limited success in delineating different types of schizophrenia on