The relationship of symptom dimensions and grey matter volume in a transdiagnostic cohort: Results from the DFG FOR2107

Introduction:

The understanding of psychiatric disorders in terms of transdiagnostic symptom dimensions across multiple psychopathological scales in both cross section and lifetime is very limited.

As of now, there are few studies investigating the relationship between factor dimensions and various brain parameters, such as gray matter volume within large transdiagnostic cohorts. Various studies have shown a 5-factor model explaining the symptom dimensions (Reininghaus et al., 2012). For the present study we used a dimensional approach that interprets different patient groups as a continuum of symptoms. In a previous analysis we established a transdiagnostic model which includes 7 factors: depressed mood, negative symptoms, delusions, formal thought disorders, hallucinations, mania and increased appetite. The aim of this study is to investigate the correlation of these symptom dimensions with gray matter volume in different patient groups.

Methods:

First, a sample of the DFG FOR2107 cohort (N = 811) consisting of patients suffering from major depressive disorder (n = 590), bipolar disorder (n = 106), schizoaffective disorder (n = 45), and schizophrenia (n = 70) was investigated in terms of the psychopathological factor structure mentioned above. Subsequently, the impact of these factors on gray matter volume (voxel-based morphometry) was examined. All subjects were scanned with a T1-weighted sequence in a 3-Tesla Siemens TIM Trio scanner at the Department of Psychiatry and Psychotherapy in Marburg and Münster. Images were pre-processed as implemented in the SPM12 toolbox. For multiple regression, smoothed modulated gray matter volumes of each subjects were used.

Results:

Multiple regression analysis showed both negative and positive effects concerning the influence of factor dimensions on gray matter volume. After statistical correction (FDR) there were only negative effects left regarding the factors negative symptoms, delusions and hallucinations. The factor negative symptoms was associated with decreased volume in the right supramarginal gyrus and the cerebellum. The most pronounced negative effects of the factor delusions were found in the left temporal gyrus, the left hippocampus, the amygdala and the right anterior insula, among others. With regard to the factor hallucinations, the most important clusters displaying decreased volume were in the thalamus, the left inferior temporal gyrus, and the left middle frontal gyrus.

Conclusion:

The presented results show that the factors negative symptoms, delusions and hallucinations are significantly related to gray matter volume reductions in certain brain areas. These areas can be associated with functions including speech perception and production as well as the perception of faces and emotions. Subsequent analyses will investigate the correlation of lifetime psychopathology with gray matter volume.

 

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