Using higher-order statistical analysis, an association between positive symptom dimensions and reduced gray matter concentration in the inferior temporal and fusiform gyri has been revealed in patients with schizophrenia, according to a study published in Schizophrenia Research.

The investigators of this study sought to understand the association between gray matter measures (concentration, volume, and cortical thickness) and symptom dimensions (perception, cognition, delusions, hallucinations, and suspiciousness) in schizophrenia.

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The study sample included 337 patients with confirmed schizophrenia who participated in 2 major studies in the United States and 1 in Norway. Structural MRI data and scores from the positive and negative syndrome scale (PANSS) were provided for all participants in each study. The investigators performed parallel independent component analysis (pICA) — a higher order statistical technique — to determine associations between gray matter concentrations (based on smoothed, normalized MRI data) with linear combinations of PANSS items (based on raw PANSS scores). Validation tests were further performed to ensure pICA estimates were consistent with the original study findings.

The pICA revealed an association between a distinct PANSS profile (characterized by increased delusional symptoms, hallucinatory behavior, suspiciousness, and anxiety) with a structural pattern of reduced gray matter concentration in the inferior temporal gyri and fusiform gyri and increased gray matter concentration in the precentral and postcentral gyri. In validation tests, the pICA showed a high correlation with the original findings. The investigators were further able to map specific symptom dimensions onto patterns of gray matter covariation, indicating that cortical abnormalities of specific regions are indeed strongly associated with the pathophysiology of schizophrenia.


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The investigators suggest that techniques like pICA can reveal meaningful insights into the underlying psychopathology of schizophrenia, in which altered brain networks are functionally related to single symptoms or specific symptom profiles. Using higher-order statistical analysis can identify patterns across different data modalities, helping identify biologically informed phenotypes, and may improve future treatment targets.

Reference

Mennigen E, Jiang W, Calhoun VD, et al. Positive and general psychopathology associated with specific gray matter reductions in inferior temporal regions in patients with schizophrenia [published online February 25, 2019]. Schizophr Res. doi: 10.1016/j.schres.2019.02.010