MEDIAL TEMPORAL-LOBE STRUCTURES IN SCHIZOPHRENIA - RELATIONSHIP OF SIZE TO DURATION OF ILLNESS

Reductions in the size of medial temporal lobe structures in schizophr enia have been demonstrated using magnetic resonance imaging. It is no t clear whether these neuropathological changes are present premorbidl y or if they reflect an adult-onset progressive process. In this study , quantitative measures were made of the lateral ventricles, third ven tricle, amygdala, hippocampus, and cerebral hemispheres from coronal M RI images on 33 patients with schizophrenia and 41 normal controls. Im ages were selected a priori from the region of the temporal lobe in wh ich we had previously demonstrated reduced volume of temporal lobe gra y matter in a separate sample of patients. Results showed a decrease i n amygdala, hippocampal, and amygdala-hippocampal size bilaterally and an increase in third and lateral ventricular volume. Advancing age in normals was associated with a decrease in the size of medial temporal structures and an increase in lateral ventricular size. In schizophre nia, there was a correlation between age and lateral ventricle size, b ut duration of illness was not associated with reductions in medial te mporal tissue or ventricular enlargement. These results are consistent with prior evidence from neuroimaging and postmortem studies of media l temporal pathology in schizophrenia and support hypotheses that neur opathological changes in schizophrenia are not progressive.