Regionally specific cortical thinning and gray matter abnormalities in the healthy relatives of schizophrenia patients.

Accumulated evidence suggests that schizophrenia is associated with subtle gray matter deficits throughout the cerebral cortex and regional cortical thinning. Although findings are not entirely consistent, healthy relatives of schizophrenia patients also show abnormalities in cortical gray matter volume, suggesting that this may be one aspect of an unexpressed genetic liability to the disorder. Cortical thickness and surface area are additional indicators of cortical cytoarchitectural integrity. To investigate the nature of cortical abnormalities in the healthy relatives of patients, this study used magnetic resonance imaging to evaluate gray matter volume, surface area, and thickness of 13 regions using an automated parcellation methodology. Compared with controls (n = 22), relatives (n = 19) had decreased volume and surface area in the right cingulate gyrus, a bilateral decrease in cingulate thickness, and decreased surface area in the superior temporal lobe. In addition, relatives had a subtle increase in gray matter volume and surface area in the left hemisphere, bilaterally in the parahippocampal gyri, and in the left middle temporal lobe. The results of this study suggest that the cortical regions most affected by the unexpressed genetic liability to schizophrenia may be the cingulate and temporal regions--regions associated with higher level cognitive, affective, and memory functions.