Structural neuroimaging in schizophrenia. An integrative view of neuromorphology

The use of structural magnetic resonance imaging (MRI) in studies of schizophrenia has resulted in a more detailed picture of anatomic areas which may be altered in this syndrome. Thus far, there have been over 130 studies of schizophrenia using MRI and, taken together, they present a clear picture of a group of disorders with altered brain structure. Their major finding is a confirmation of the older pneumoencephalography and computertomography studies showing an enlargement of lateral ventricles and a volume reduction seen in the temporal lobe. When structural studies are carried out in other cortical and subcortical regions, however, the volume reduction is not so uniform, but rather restricted to certain areas in a given patient. In addition medication effects can be seen especially in the caudate nucleus which tend to increase in volume after long-term neuroleptic drug usage and again normalize under the atypical drug clozapine. These data are consistent with a neurodevelopmental model of schizophrenia and with some kind of progressive neurodegenerative process. This review suggests that an integrative model with initial developmental errors may underlie the majority of cases of schizophrenia, but that cases of chronic schizophrenia appear to involve progressive neurodegeneration. In assessing the scatter in available data, it appears that there is no consistent neuropathology across all cases of schizophrenia and preferential areas of dysfunction can be determined. Thus, there seems a collection of subtle neurodevelopmental errors which can lead to various forms of schizophrenia and that at least some types of schizophrenia most probably also involve a neurodegenerative process which could in fact be a consequence of the initial developmental defect.