Cortical thinning in relation to impaired insight into illness in patients with treatment resistant schizophrenia

Abstract

Impaired insight into illness is a common element of schizophrenia that contributes to treatment nonadherence and negative clinical outcomes. Previous studies suggest that impaired insight may arise from brain abnormalities. However, interpretations of these findings are limited due to small sample sizes and inclusion of patients with a narrow range of illness severity and insight deficits. In a large sample of patients with schizophrenia, the majority of which were designated as treatment-resistant, we investigated the associations between impaired insight and cortical thickness and subcortical volumes. A total of 94 adult participants with a schizophrenia spectrum disorder were included. Fifty-six patients (60%) had treatment-resistant schizophrenia. The core domains of insight were assessed with the VAGUS insight into psychosis scale. We obtained 3T MRI T1-weighted images, which were analysed using CIVET and MAGeT-Brain. Whole-brain vertex-wise analyses revealed impaired insight, as measured by VAGUS average scores, was related to cortical thinning in left frontotemporoparietal regions. The same analysis in treatment-resistant patients showed thinning in the same regions, even after controlling for age, sex, illness severity, and chlorpromazine antipsychotic dose equivalents. No association was found in non-treatment-resistant patients. Region-of-interest analyses revealed impaired general illness awareness was associated with cortical thinning in the left supramarginal gyrus when controlling for covariates. Reduced right and left thalamic volumes were associated with VAGUS symptom attribution and awareness of negative consequences subscale scores, respectively, but not after correction for multiple testing. Our results suggest impaired insight into illness is related to cortical thinning in left frontotemporoparietal regions in patients with schizophrenia, particularly those with treatment resistance where insight deficits may be more chronic.

Associations Between Structural Covariance Network and Antipsychotic Treatment Response in Schizophrenia

“…Notably, it has been reported that patients with TRS exhibit widespread and stronger cortical alterations compared with patients with non-TRS [22][23][24][25]. Fan et al also reported that the cognitive impairment in the patients with TRS was largely mediated by cortical thickness of frontal, temporal, and parietal areas, suggesting cortical thinning might be associated with the pathophysiology of treatment resistance in schizophrenia and an important biomarker of those patients [26].…”

Histological Study on the Thickness of Gray Matter at the Summit and Bottom of Folium in Different Age Groups of Bangladeshi People

“…The cortical thickness has piqued the curiosity of researchers studying normal development and a wide range of neurodegenerative and mental illnesses-variations of the thickness of GM that can manifest in normal aging [23,24]. Cortical thinning is related to the atrophy of brain material, which can reveal much about the evolution and contributory factors of diseases [25], for example, Alzheimer's disease (AD) [26,27] and other dementias [27,28], Parkinson's disease [26,[28][29][30]], Huntington's disease [31,32], corticobasal degeneration [33,34], amyotrophic lateral sclerosis [35,36], and schizophrenia [37,38]. Multiple studies revealed that reduced cortical width is a sign of neurodegeneration associated with obesity, high body mass index (BMI), profound psychiatric illnesses, and AD.…”