Neuropsychological correlates of cognitive insight in schizophrenia.

Clinical practice has highlighted a possible discrepancy between patient's verbal assertions, called clinical insight, and the actual convictions about the illness, called emotional insight. The complementary construct of cognitive insight refers to the cognitive processes involved in self-reflection and the ability to modify erroneous beliefs and misinterpretations. The aim of this study was to determine the psychopathological and neuropsychological predictors of cognitive insight in schizophrenia. Sixty outpatients with Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) schizophrenia diagnosis were administered the Beck Cognitive Insight Scale, the Positive and Negative Symptom Scale (PANSS), and a comprehensive neuropsychological battery. Results indicate that poor global cognitive insight in schizophrenia is significantly related to lower visual working memory, while a higher self-overconfidence is significantly related to deficits in verbal and visual memory and to the failure in using external information to correct erroneous convictions. Thus, our study suggests that impaired cognitive insight depends mainly on reduced working memory and executive function performances. These findings highlight the fundamental importance of the development of specific therapeutic strategies to improve the metacognitive components of insight in order to enhance treatment adherence in schizophrenia.

Reduced fronto-temporal connectivity is associated with frontal gray matter density reduction and neuropsychological deficit in schizophrenia.

OBJECTIVES: A "disconnectivity model" of schizophrenia has been proposed, but it is still unclear if white matter abnormalities are associated with gray matter changes and if they may be the anatomic substrate of cognitive impairment, which is a core symptom of the disorder. The first objective was to detect if white matter microstructure alterations in schizophrenia are associated with or independent of gray matter change, using an optimized method for white matter (Tract-Based Spatial Statistics) and gray matter analyses (whole-brain voxel-wise approach). The second objective was to identify the neuropsychological correlates of white matter abnormalities in the schizophrenic group, using a comprehensive neuropsychological battery. METHODS: In this case-control study 43 schizophrenic patients and 43 healthy volunteers were consecutively enrolled and matched for age and gender. RESULTS: Fractional anisotropy reduction was found in 6 fronto-temporal clusters (corrected p-values <0.05) in schizophrenic group in comparison with healthy volunteers, and 3 clusters showed fractional anisotropy increase (corrected p-values <0.05). Two of the clusters showing reduced fractional anisotropy were associated with reduced gray matter density in neuroanatomically-related regions in schizophrenic subjects (p-values ranging from 0.001 to 0.026). Executive, constructional-praxis, and working memory deficits were significant predictors of fractional anisotropy reduction in 4 clusters in the schizophrenic group (p-values ranging from <0.0001 to 0.0017). CONCLUSIONS: Our data support the disconnectivity hypothesis in schizophrenia, enlightening a link between reduced fronto-temporal connectivity and "frontal" cognitive deficits. Reduced gray matter density may be involved primarily in the pathogenesis of some of these disconnected areas.

The language of schizophrenia: an analysis of micro and macrolinguistic abilities and their neuropsychological correlates.

Language disturbance is one of the main diagnostic features in schizophrenia and abnormalities of brain language areas have been consistently found in schizophrenic patients. The main aim of this study was to describe the impairment of micro and macrolinguistic abilities in a group of twenty-nine schizophrenic patients during the phase of illness stability compared to forty-eight healthy participants matched for age, gender and educational level. Microlinguistic abilities refer to lexical and morpho-syntactic skills, whereas macrolinguistic abilities relate to pragmatic and discourse level processing. Secondary aims were to detect the effect of macrolinguistic on microlinguistic ability, and the neuropsychological impairment associated with the linguistic deficit. The linguistic assessment was performed on story-telling. Three narratives were elicited with the help of a single-picture stimulus and two cartoon stories with six pictures each. A modified version of the Mental Deterioration Battery was used to assess selective cognitive performances. A series of t-tests indicated that all the macrolinguistic variables were significantly impaired in schizophrenic patients in at least one of the three story-tellings. Furthermore, the limited impairment found in microlinguistic abilities was influenced by macrolinguistic performance. Multivariate stepwise regression analyses suggested that reduced attention performances and deficit in executive functions were predictors of linguistic impairment. Language production in schizophrenia is impaired mainly at the macrolinguistic level of processing. It is disordered and filled with irrelevant pieces of information and derailments. Such erratic discourse may be linked to the inability to use pragmatic rules and to cognitive deficits involving factors such as attention, action planning, ordering and sequencing.

Hippocampi, thalami, and accumbens microstructural damage in schizophrenia: a volumetry, diffusivity, and neuropsychological study.

Volumetric abnormalities in the subcortical structures have been described in schizophrenia. However, it still has to be clarified if subtle microstructural damage is also present. Thus, we aimed to detect subcortical volume and mean diffusivity (MD) alterations in 45 patients with diagnosis of schizophrenia compared with 45 age-, gender-, and educational attainment-matched healthy comparison (HC) participants, by using a combined volumetry and diffusion tensor imaging (DTI) method. A secondary aim was to identify the neuropsychological correlates of subcortical abnormalities in the schizophrenic group. We found thalami and hippocampi bilaterally and left accumbens to show MD increase in the schizophrenic group. No volumetric decrease was found. Moreover, significant correlations between the MD values in subcortical structures (right thalamus and hippocampus and left accumbens) and working memory performance were found. Thus, subcortical microstructural alterations are present in schizophrenia even in absence of volumetric abnormalities. Furthermore, microstructural damage in subcortical areas is linked to working memory, suggesting the presence of a subtle microstructural subcortical dysfunction in the pathoetiological mechanism underlying high cognitive load performances in schizophrenia. Finally, our findings indicate that MD is a more sensitive marker of brain tissue deficits than signal intensity variations measured in T1-weighted imaging data, consistently with previous reports. Thus, DTI appears to be an invaluable tool to investigate subcortical pathology in schizophrenia, greatly enhancing the ability to detect subtle brain changes in this complex disorder.