HETEROGENEITY OF THE PSYCHOSES - IS THERE A NEURODEGENERATIVE PSYCHOSIS

Whereas etiological heterogeneity of the various types of schizophreni a has been repeatedly proposed, relatively few attempts have been made to separate the component diseases. Using a strategy focusing on bimo dal distributions within several relevant domains of schizophrenia, we demonstrate that currently available data on schizophrenia patients a re consistent with the hypothesis that some of these patients have an ongoing neurodegenerative disease, whereas others do not. We review st udies (longitudinal and cross-sectional) documenting progressive incre ases in ventricular size, accelerated loss of brain tissues, progressi ve delays in treatment response, and neurochemical (magnetic resonance spectroscopy) and neurophysiological (P300) indices, all of which are consistent with ongoing cerebral degeneration in a significant subgro up of schizophrenia patients. These lines of evidence converge on a co nceptualization of schizophrenia as being composed of several etiologi cally distinct processes, with one subset of psychotic patients eviden cing progressive brain degeneration. We conclude with a discussion of possible etiologies for this condition.