Gray and white matter volume abnormalities in generalized anxiety disorder by categorical and dimensional characterization

Abstract

Increasing efforts have been made to investigate the underlying pathophysiology of generalized anxiety disorder (GAD), but only limited consistent information is available on gray (GM) and white matter (WM) volume changes in affected adults. Additionally, few studies employed dimensional approaches to GAD pathology. This study compares structural brain imaging data from n = 19 GAD subjects and n = 24 healthy comparison (HC) subjects, all medication-free and matched on age, sex and education. Separate categorical and dimensional models were employed using voxel-based morphometry for GM and WM. Significantly higher GM volumes were found in GAD subjects mainly in basal ganglia structures and less consistently in the superior temporal pole. For WM, GAD subjects showed Significantly lower volumes in the dlPFC. Largely consistent findings in dimensional and categorical models point toward these structural alterations being reliable and of importance for GAD. While lower volume in the dlPFC could reflect impaired emotional processing and control over worry in GAD, basal ganglia alterations may be linked to disturbed gain and loss anticipation as implicated in previous functional GAD studies. As perturbations in anticipation processes are central to GAD, these areas may warrant greater attention in future studies.

Dynamic changes of amplitude of low‐frequency fluctuations in patients with generalized anxiety disorder

“…The abnormal dALFF detected in these regions is consistent with previous studies suggesting that GAD patients exhibit impaired TOM reasoning for negative social stimuli (Kohn et al, 2014), with structural and functional abnormalities in regions associated with social cognition, such as abnormal rsFC of the fusiform gyrus with limbic regions (Cui et al, 2016;Molent et al, 2018) and aberrant cortical morphology and white matter integrity of the ITG and TP (Hilbert et al, 2015;Molent et al, 2018;Strawn et al, 2013).…”

Cortical thickness and subcortical structure volume abnormalities in patients with major depression with and without anxious symptoms

“…Previous fMRI study found that compared MDD and healthy controls, comorbidity of depression and anxiety had more activation in the caudate during rejections part of Parametric Go/No-Go task (Crane et al, 2016). A structure study reported that subjects with anxiety disorder showed larger right striatum volume compared with controls, and the worry severity and volume of the left caudate nucleus positively correlated (Hilbert et al, 2015).…”

Intolerance of uncertainty predicts increased striatal volume.

“…Of particular relevance to the current study, Hilbert and colleagues (2015) reported that increased striatal volumes not only differentiated healthy individuals from those with GAD at a categorical level, but also on a dimensional level, as self-reported measure of IU positively correlated with putaminal volume when both groups were pooled into a single study sample. Our findings contribute to this work by demonstrating that increased striatal volumes as a function of elevated IU can be observed within healthy individuals.…”