Search

Structural brain abnormalities have consistently been found in patients with schizophrenia. Diffusion tensor imaging (DTI) has been shown to be a useful method to measure white matter (WM) integrity in this illness, but findings in the earlier disease stages are inconclusive. Moreover, the relationship between WM microstructure and the familial risk for developing schizophrenia remains unresolved. From 126 patients with schizophrenia, 123 of their non-psychotic siblings and 109 healthy control subjects, DTI images were acquired on a 1.5 T MRI scanner. Mean fractional anisotropy (FA) was compared along averaged WM tracts, computed for the genu, splenium, left and right uncinate fasciculus, cingulum, inferior fronto-occipital fasciculus, fornix, arcuate fasciculus, and inferior longitudinal fasciculus. Fractional anisotropy (FA) was assessed for its unique environmental and familial (possibly heritable) aspects associated with schizophrenia, using structural equation modeling for these white matter tracts. The results of this study show that young adult (mean age 26.7 years) patients with schizophrenia did not differ in mean FA from healthy controls along WM fibers; siblings of patients showed higher mean FA in the left and right arcuate fasciculus as compared to patients and controls. With increasing age, an excessive decline in mean FA was found in patients as compared to siblings and healthy controls in the genu, left uncinate fasciculus, left inferior fronto-occipital fasciculus, and left inferior longitudinal fasciculus. Moreover, symptom severity was negatively correlated to mean FA in the arcuate fasciculus bilaterally in patients with schizophrenia. In young adult patients with schizophrenia integrity of individual tract-based (corticocortical) fibers can (still) be within normal limits. However, changes in the arcuate fasciculus may be relevant to (the risk to develop) psychosis, while a general and widespread loss of fiber integrity may be related to illness progression., (Copyright © 2012 Elsevier B.V. and ECNP. All rights reserved.)

Background: It remains unclear whether structural brain abnormalities in schizophrenia are caused by genetic and/or disease-related factors. Structural brain abnormalities have been found in nonpsychotic first-degree relatives of patients with schizophrenia, but results are inconclusive. This large magnetic resonance imaging study examined brain structures in patients with schizophrenia, their nonpsychotic siblings, and healthy control subjects using global and focal brain measurements., Methods: From 155 patients with schizophrenia, their 186 nonpsychotic siblings, and 122 healthy controls (including 25 sibling pairs), whole-brain scans were obtained. Segmentations of total brain, gray matter (GM), and white matter of the cerebrum, lateral and third ventricle, and cerebellum volumes were obtained. For each subject, measures of cortical thickness and GM density maps were estimated. Group differences in volumes, cortical thickness, and GM density were analyzed using Structural Equation Modeling, hence controlling for familial dependency of the data., Results: Patients with schizophrenia, but not their nonpsychotic siblings, showed volumetric differences, cortical thinning, and reduced GM density as compared with control subjects., Conclusions: This study did not reveal structural brain abnormalities in nonpsychotic siblings of patients with schizophrenia compared with healthy control subjects using multiple imaging methods. Therefore, the structural brain abnormalities observed in patients with schizophrenia are for the largest part explained by disease-related factors.