The insula–claustrum region and delusions in schizophrenia

Abstract

Objective

We examined the relationship between cerebral gray matter (GM) volume and severity of delusions and hallucinations in adults with schizophrenia.

Method

MRI scans in 43 patients with schizophrenia were acquired. Correlations were computed between GM volume and clinician ratings of hallucinations and delusions.

Results

The analysis revealed significant inverse correlations between ratings of the severity of delusions and volumes of the left claustrum and right insula. Significant correlations were not observed between cerebral GM volume and ratings of hallucinations.

Conclusion

The insula/claustrum region may be critical to the experience of delusions and more careful scrutiny of the claustrum in relation to schizophrenia appears warranted.

Introduction

Schizophrenia (SZ) is characterized by three partially overlapping domains of symptoms. These include positive, negative and disorganized symptoms. With the advent of neuroimaging techniques, attempts have been made to correlate symptoms of schizophrenia with brain structure and function in order to better characterize the pathophysiology of SZ. Using voxel-based morphometry or VBM (Ashburner and Friston, 2000), investigators have correlated regional cerebral gray matter (GM) volume or concentration with schizophrenia subtypes, global ratings of positive symptoms, as well as specific positive symptoms (McCarley et al., 1999, Ha et al., 2004, Pressler et al., 2005, Koutsouleris et al., 2008, Cascella et al., 2010, Nenadic et al., 2010a, Nenadic et al., 2010b). Imaging studies using region-of-interest (ROI) measurements have also found associations between volume changes in the temporal cortex (superior temporal gyrus and middle temporal lobe) and positive symptoms in schizophrenia, including hallucinations, delusions, and thought disorder (Barta et al., 1990, Barta et al., 1997, Shenton et al., 1992, Bogerts et al., 1993, McCarley et al., 1993, Flaum et al., 1995).

Applications of current VBM techniques have confirmed correlations of positive symptoms with temporal structures, as well as the prefrontal cortex and subcortical structures, such as the thalamus and the basal ganglia (Wright et al., 1995, Gaser et al., 2004, Koutsouleris et al., 2008, Nenadic et al., 2010b). As a follow-up to our earlier report of structural brain abnormalities associated with prominent negative symptoms of SZ, i.e., patients with the deficit syndrome (Cascella et al., 2010), the goal of this study was to extend our investigation of GM abnormalities associated with the presence and the severity of positive symptoms, specifically, hallucinations and delusions.