White matter defects in first episode psychosis patients: A voxelwise analysis of diffusion tensor imaging

Patterns of Brain Structural Changes in First-Contact, Antipsychotic Drug-Naïve Patients with Schizophrenia

“…[4][5][6][7][8] Different from other studies of first-episode antipsychotic drug-naïve patients with schizophrenia, [4][5][6][7][8][9] we observed that patients also showed regions of increased FA and decreased MD values, likely reflecting structural "hyperconnectivity," 18 mainly in the brain stem, cerebellum, and in the interhemispheric and cortico-cortical WM connections. Some studies of patients with schizophrenia have found a similar pattern of DTI changes.…”

“…It is clear that studies based on untreated patients enrolled at an early stage of the disease represent the easiest and most rewarding strategy to overcome such an issue. To date, however, only a few studies [4][5][6][7][8][9] have adopted this strategy showing WM changes compared with healthy participants in a variable pattern of brain regions including the splenium of the corpus callosum, 4,6 superior longitudinal fasciculus, 7,8 anterior 9 and posterior 4 limbs of the internal capsule, and fronto-occipital fasciculus. 4 The relevance of DTI abnormalities in the early phase of schizophrenia is further supported by the positive association between positive symptoms and fractional anisotropy (FA) values of the superior and inferior longitudinal fasciculi and inferior fronto-occipital fasciculus in never-medicated patients with schizophrenia.…”

“…4 The relevance of DTI abnormalities in the early phase of schizophrenia is further supported by the positive association between positive symptoms and fractional anisotropy (FA) values of the superior and inferior longitudinal fasciculi and inferior fronto-occipital fasciculus in never-medicated patients with schizophrenia. 5,10 In addition, most studies [4][5][6][7][8] have investigated FA only, and none of them have assessed GM volumes in the same sample.…”

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

“…This may reflect reduced axonal number or packing density, cellular membrane abnormalities that increase permeability including possible loss of myelin, or inconsistent fiber orientation. These findings may be confounded by exposure to nonclozapine psychotropic medications; however, concurrent findings in studies involving subjects who are naive to psychotropic medication (Cheung et al, 2008;Gasparotti et al, 2009;Karlsgodt et al, 2009;Perez-Iglesias et al, 2010a;Zou et al, 2008) supporting the hypothesis that a portion of these deficits are due to the pathophysiology of schizophrenia. Postmortem studies provide support for a contribution of reduced axonal packing density, abnormal glial cell arrangement or function, and reduced myelin in schizophrenia.…”

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.…”