Baseline and follow-up mesiotemporal volumes in first episode schizophrenics

Structural abnormalities of the mesiotemporal (MT) lobe have been proposed as a probable neurodevelopmental abnormality in schizophrenia. Although reductions in the volumes of MT structures in these areas have been demonstrated in schizophrenia, so tar these reductions have been reported only in relatively small samples of first episode patients; a population important to study as they exclude confounding effects of advanced age, institutionalization, chronic illness and treatment. We investigated anterior and posterior mesiotemporal volumes in 85 first episode patients and 25 age and sex matched controls at baseline and follow-up examinations. Flash images were acquired on a 1.0 Tesla whole body MR system providing 3.1mm slices and in-plane resolution of 1mm × 1mm. Measurements were made by a blind rater using a semi-automated computer mensurated system. Delineation of regions of interest were based upon post-mortem histological studies. Results indicated a highly significant smaller volume of all 4 mesiotemporal regions in schizophrenics (p<0.0001) with decreases ranging from 9% to 26%. The anterior portion of the amygdala/hippocampal complex (comprising amygdala and anterior hippocampus) bilaterally showed the greatest degree of volume reduction. No significant changes in patient volume measurements over time were found. Our results support the hypothesis that MT volume changes are present in schizophrenia and that this abnormality extends to the onset of first break psychosis.