Subcortical and temporal structures in affective disorder and schizophrenia: a magnetic resonance imaging study

Volumetric measurements of subcortical and temporal structures were done on a sample of 54 schizophrenic patients, who were compared with 48 bipolar patients and 47 normal controls. We observed the male schizophrenic patients to have significant enlargement in the putamen and lesser enlargement in the caudate. We found the right temporal lobe to be larger than the left across all diagnostic groups, although bipolar females failed to have this asymmetry. We did not replicate the finding of decreased hippocampal, amygdala, or temporal lobe volume in our schizophrenic patients. Nor did we find significant differences between our bipolar patients and controls in the structures measured, with the exception of the right hippocampus. Our findings are consistent with a developmental defect in pruning of subcortical brain regions or with a compensatory synaptic increase secondary to decreased input from other brain regions such as the prefrontal cortex or anterior temporal lobe structures. Coupled with the lack of temporal lobe asymmetry in bipolar females, these findings suggest that different types of gender-specific neurodevelopmental abnormalities may occur in affective versus schizophrenic psychosis, which may reflect the effects of hormonal influences on brain development in predisposed individuals.