Altered Cortical Thickness Related to Clinical Severity But Not the Untreated Disease Duration in Schizophrenia

Abstract

Although previous studies have reported deficits in the gray matter volume of schizophrenic patients, it remains unclear whether these deficits occur at the onset of the disease, before treatment, and whether they are progressive over the duration of untreated disease. Furthermore, the gray matter volume represents the combinations of cortical thickness and surface area; these features are believed to be influenced by different genetic factors. However, cortical thickness and surface area in antipsychotic-naive first-episode schizophrenic patients have seldom been investigated. Here, the cortical thicknesses and surface areas of 128 antipsychotic-naive first-episode schizophrenic patients were compared with 128 healthy controls. The patients exhibited significantly lower cortical thickness, primarily in the bilateral prefrontal and parietal cortex, and increased thickness in the bilateral anterior temporal lobes, left medial orbitofrontal cortex, and left cuneus. Furthermore, decreased cortical thickness was related to positive schizophrenia symptoms but not to the severity of negative symptoms and the untreated disease duration. No significant difference of surface area was observed between the 2 groups. Thus, without the confounding factors of medication and illness progression, this study provides further evidence to support anatomical deficits in the prefrontal and parietal cortex early in course of the illness. The increased thicknesses of the bilateral anterior temporal lobes may represent a compensatory factor or may be an early-course neuronal pathology caused by preapoptotic osmotic changes or hypertrophy. Furthermore, these anatomical deficits are crucial to the pathogenesis of positive symptoms and relatively stable instead of progressing during the early stages of the disease.

Prefrontal cortical thinning links to negative symptoms in schizophrenia via the ENIGMA consortium

“…In patients with schizophrenia, Venkatasubramanian et al (2008) found that lower left MOFC thickness was associated with higher negative symptom severity. Similar findings have been reported by Nenadic et al (2015), providing further evidence for the involvement of medial prefrontal regions in negative symptoms; though some negative findings also exist (CrespoFacorro et al 2011;Xiao et al 2015).…”

“…However, there have also been reports, which failed to identify an association between MOFC thickness and negative symptoms (Xiao et al 2015;Bodnar et al 2014;Ansell et al 2015;McKechanie et al 2015). There are several potential explanations for these discrepant findings.…”

The neurobiology of transition to psychosis

“…30 Grey matter increase in patients with psychosis has now been reported in both crosssectional studies of treated [31][32][33] and neuroleptic-naive patients 34,35 and in longitudinal studies [36][37][38][39][40][41] in which patients were treated with antipsychotics. Dukart and colleagues report that a medium to large effect size of increase in grey matter tissue can occur even before the onset of psychosis in individuals with ARMS.…”

Altered cortical structures and tract integrity of the mirror neuron system in association with symptoms of schizophrenia

“…It is possible that negative symptoms developed along the illness course and turn out to be important indicators of reduced cortical volume as disease progressed. One latest publication found that the cortical thickness of the regions with reduced cortical thickness, i.e., the right dorsolateral prefrontal cortex, bilateral precentral gyri, left orbitofrontal cortex, and left inferior frontal gyrus pars triangularis, was negatively correlated with positive symptom severity in 128 drug-naïve patients with schizophrenia (Xiao et al, 2015). Associations between the cortical thickness of the right SMg and positive symptoms were shown in our study of antipsychotictreated patients with a mean duration of illness of 9 years.…”

“…A review of functional imaging studies of social brain dysfunction in schizophrenia suggested that two MNS regions -the inferior frontal cortex and the inferior parietal lobe -were selectively responsible for some of the core cognitive manifestations of this disorder (Brunet-Gouet and Decety, 2006 individually. Alterations as identified by magnetic resonance imaging (MRI) were reported in frontal and parietal lobes (Xiao et al, 2015) as well as fronto-parietal white matter connections (Sigmundsson et al, 2001;Burns et al, 2003). It is plausible to speculate that there are alterations in the structures forming the MNS, but no study has yet been conduced in which these structures are viewed as a network.…”