Hippocampus and amygdala volumes in elderly schizophrenic patients as assessed by magnetic resonance imaging

Reduced size of the hippocampus and amygdala has been one of the more consistent morphological findings in schizophrenia, but the question of medial temporal abnormalities in elderly schizophrenia patients has been inadequately addressed. We examined 20 elderly subjects with a DSM-III-R diagnosis of schizophrenia, five of whom had a late-onset schizophrenia (LOS), and compared them with 20 healthy volunteers on magnetic resonance imaging (MRI) and neuropsychological parameters. Hippocampus and amygdala volumes were obtained by manual tracing on T1-weighted 1.5 mm thick contiguous coronal slices perpendicular to the long axis of the hippocampus. Patients had smaller left hippocampal and right amygdala volumes than comparison subjects, the mean differences being 9.7 and 11.1%, respectively, but the right amygdala volumes were not significantly different after Bonferroni correction. The hippocampus-amygdala volumes together were smaller in the schizophrenia group bilaterally. In a pilot analysis, the LOS subjects had non-significantly smaller hippocampus-amygdala volumes than did the early-onset schizophrenia (EOS) subjects. For the schizophrenia group, there were significant correlations between amygdala and hippocampus volumes and some neuropsychological performance indices. The findings are consistent with those reported in younger schizophrenics, and are of the same order of magnitude, suggesting that they are not likely to be progressive. This pilot analysis in LOS subjects argues against the condition being secondary to Alzheimer's disease.