Cortical morphology and illness insight in patients with schizophrenia

Abstract

Insight into illness in schizophrenia (SZ) patients has a major impact on treatment adherence and outcome. Previous studies have linked distinct deviations of brain structure to illness insight, specifically in frontoparietal and subcortical regions. Some of these abnormalities are thought to reflect aberrant cortical development. In this study, we used cross-sectional data to examine associations between illness insight and two cortical surface markers that are known to follow distinct neurodevelopmental trajectories, i.e. cortical gyrification (CG) and thickness (CT). CG and CT was investigated in SZ patients (n = 82) and healthy controls (HC, n = 48) using 3 T structural magnetic resonance imaging. Illness insight in SZ patients was measured using the OSSTI scale, an instrument that provides information on two distinct dimensions of illness insight, i.e. treatment adherence (OSSTI-A) and identification of disease-related symptoms (OSSTI-I). CT and CG were computed using the Computational Anatomy Toolbox (CAT12). Whole-brain and regions-of-interest (ROI)-based analyses were performed. SZ patients showed higher CG in anterior cingulate, superior frontal and temporal gyrus and reduced CG in insular and superior frontal cortex when compared to HC. SZ patients showed decreased CT in pre- and paracentral, occipital, cingulate, frontoparietal and temporal regions. Illness insight in SZ patients was significantly associated with both CG and CT in the left inferior parietal lobule (OSSTI-A) and the right precentral gyrus (CG/OSSTI-A, CT/OSSTI-I). The data support a multi-parametric neuronal model with both pre- and postnatal brain developmental factors having an impact on illness insight in patients with SZ.

Keywords: Cortical thickness; Gyrification; Insight; MRI; Schizophrenia; Surface-based morphometry.

Fig. 1

Negative and positive associations for CG and OSSTI-I and OSSTI-A. Results derived from whole-brain regression analyses implemented in SPM12, adjusted for age, gender, OLZe, PANSS (p < 0.005, uncorrected, expected voxels per cluster). CG cortical gyrification, OLZe Olanzapine equivalents, OSSTI Osnabrueck Scale of Therapeutic Attitudes and Identification of Psychological Problems in Schizophrenia (OSSTI-A adherence), OSSTI-I identification of disease-related symptoms), PANSS Positive and Negative Syndrome Scale

Fig. 2

Negative and positive associations in the multiple regression analysis for CT and OSSTI-I and OSSTI-A. Results derived from whole-brain regression analyses implemented in SPM12, adjusted for age, gender, OLZe, PANSS (p < 0.005, uncorrected, expected voxels per cluster). CT cortical thickness, OLZe Olanzapine equivalents, OSSTI Osnabrueck Scale of Therapeutic Attitudes and Identification of Psychological Problems in Schizophrenia (OSSTI-A adherence; OSSTI-I identification of disease-related symptoms), PANSS Positive and Negative Syndrome Scale