Structural brain abnormalities in patients with schizophrenia and their healthy siblings

Objective: The authors sought to investigate the contribution of genotype o n structural brain abnormalities in schizophrenia. Method: Intracranial vol umes and volumes of the cerebrum, white and gray matter, lateral and third ventricles, frontal lobes, caudate nucleus, amygdala, hippocampus, parahipp ocampal gyrus, and the cerebellum were measured in 32 same-sex siblings dis cordant for schizophrenia and 32 matched comparison subjects by means of ma gnetic resonance imaging. Results: Third ventricle volumes did not differ b etween the schizophrenic patients and their healthy siblings. However, both had higher third ventricle volumes than did the comparison subjects. The s chizophrenic patients had lower cerebrum volumes than did the comparison su bjects, whereas the cerebrum volume of the healthy siblings did not signifi cantly differ from the patients or comparison subjects. Additionally, patie nts with schizophrenia displayed a volume reduction of the frontal lobe gra y matter and a volume increase of the caudate nuclei and lateral ventricles compared to both their healthy siblings and comparison subjects. Intracran ial volume, CSF volume, or volumes of the cerebellum, amygdala, hippocampus , or the parahippocampal gyrus did not significantly differ among the patie nts, siblings, and comparison subjects. Conclusions: Healthy siblings share third ventricle enlargement with their affected relatives and may partiall y display a reduction in cerebral volume. These findings suggest that third ventricular enlargement, and to some extent cerebral volume decrease, may be related to genetic defects that produce a susceptibility to schizophreni a.