Complementary diffusion tensor imaging study of the corpus callosum in patients with first-episode and chronic schizophrenia

Abstract

Background: Abnormalities in the corpus callosum have long been implicated in schizophrenia. Previous diffusion tensor imaging (DTI) studies in patients with different durations of schizophrenia yielded inconsistent results. By comparing patients with different durations of schizo phrenia, we investigated if white matter abnormalities of the corpus callosum emerge at an early stage in the illness or result from pathological progression. Methods: We recruited patients with first-episode schizophrenia, patients with chronic schizophrenia and age-, sexand handedness-matched healthy controls. We used 2 DTI techniques (voxel-based and fibre-tracking DTI) to investigate differences in corpus callosum integrity among the 3 groups. Results: With both DTI techniques, significantly decreased fractional anisotropy values were identified in the genu of corpus callosum in patients with chronic schizophrenia, but not first-episode schizophrenia, compared with healthy controls. Limitations: This study was cross-sectional, and the sample size was relatively small. Conclusion: Abnormalities in the genu of the corpus callosum might be a progressive process in schizophrenia, perhaps related to disease severity and prognosis.

Altered Interhemispheric and Temporal Lobe White Matter Microstructural Organization in Severe Chronic Schizophrenia

“…Diffusion-weighted imaging has been relatively consistent in reporting reduced callosal FA in chronic schizophrenia (Douaud et al, 2007;Koch et al, 2010;Kubicki et al, 2008;Miyata et al, 2010;Mori et al, 2007b;RotarskaJagiela et al, 2008), including during remission (Koch et al, 2010) and less consistently in studies examining individuals at the first episode (Cheung et al, 2008;Gasparotti et al, 2009;Perez-Iglesias et al, 2010b;Peters et al, 2008;Price et al, 2005;Szeszko et al, 2005) or in earlier stages of illness (Davenport et al, 2010;Douaud et al, 2007;Kyriakopoulos and Frangou, 2009). Directly comparing first episode and chronic groups supports more severe changes in FA in the genu of the corpus callosum (Friedman et al, 2008;Kong et al, 2011), the left ILF (Friedman et al, 2008), and ALIC (Bora et al, 2011) in the chronic group including relative to the first episode group. By contrast, the large scale metaanalysis by Bora et al (2011) has reported the opposite, specifically for the genu of the corpus callosum, with FA being lower in the first episode relative to the chronic group with schizophrenia.…”

“…In WM, a single study of individuals experiencing their first psychotic episode did not detect microstructural changes (as assessed by DTI) in the corpus callosum relative to healthy controls (Price et al, 2005). Studies including both first episode and chronic patients showed that patients with chronic disease had significantly reduced FA compared with controls, reaching only a trend level in first episode patients (Friedman et al, 2008;Kong et al, 2011). This implies a progressive nature associated with illness duration in schizophrenia, as previously reported in a structural study investigating GM and WM volumes reporting a progressive reduction in the frontal WM volume in patients (Ho et al, 2003).…”

“…Recent meta-analyses of voxel-based imaging studies showed widespread clusters of GM volume reductions with no regions of volume increases, and widespread WM deficity in schizophrenia (Bora et al, 2011). Abnormalities in WM detected using diffusion MRI may indicate alterations in commissural and association fibers connecting GM regions (Ellison-Wright and Bullmore, 2009), Moreover, progressively more severe deficits in WM anisotropy have been found in crosssectional studies comparing first episode and chronic patients (Friedman et al, 2008;Kong et al, 2011).…”

“…The most consistently implicated WM bundles in chronic schizophrenia samples include the genu of the corpus callosum (Kong et al, 2011;Kubicki et al, 2008;RotarskaJagiela et al, 2008;Whitford et al, 2010), the splenium of the corpus callosum (Agartz et al, 2001;Foong et al, 2000), anterior cingulate (Camchong et al, 2011;Sun et al, 2003;Wang et al, 2004), and anterior limb of the internal capsule (ALIC) (Buchsbaum et al, 1998;Sussmann et al, 2009). However, none of these studies were specifically carried out on a treatment-resistant clozapine-naive group, and clozapine has previously been reported to cause structural changes in the brain (Ho et al, 2003;Molina et al, 2005;Scheepers et al, 2001).…”

Emotional and Motivational Processes in Bipolar Disorder: A Neural Network Perspective

“…Although causality still needs to be proven, there is notable evidence suggesting that impaired white matter integrity in the corpus callosum, the anterior limb of the internal capsule, and the uncinate fasciculus might be biological vulnerability factors of bipolar disorder. However, enthusiasm for this assumption has been limited by the fact that reductions of white matter integrity, especially of the corpus callosum [221][222][223][224][225][226][227][228], the anterior limb of the internal capsule, and the uncinate fasciculus, have also been reported for schizophrenia and unipolar depression [173,183,[229][230][231][232][233]. Thus, reported white matter abnormalities might not be a vulnerability specific to bipolar disorder, but they seem linked to clinical features like impulsivity, psychosis, and depressive mood as well.…”