Abnormalities in gray and white matter volumes associated with explicit memory dysfunction in patients with generalized anxiety disorder

Background The neuroanatomical abnormalities associated with behavioral dysfunction on explicit memory in patients generalized anxiety disorder (GAD) have not yet been clearly identified. Purpose To investigate the regional gray matter (GM) and white matter (WM) volume alterations over the whole brain in patients with GAD, as well as the correlation between the brain structural abnormality and explicit memory dysfunction. Material and Methods Twenty patients with GAD and 20 healthy controls matched for age, sex, and education level underwent high-resolution T1-weighted magnetic resonance imaging (MRI). The participants performed the explicit memory tasks with the neutral and anxiety-inducing words. Results Patients with GAD showed significantly reduced GM volumes in the midbrain (MB), thalamus, hippocampus (Hip), insula, and superior temporal gyrus (STG); and reduced WM volumes in the MB, anterior limb of the internal capsule (ALIC), dorsolateral prefrontal cortex (DLPFC), and precentral gyrus (PrG). It is important to note that the GM volume of the Hip and the WM volume of the DLPFC were positively correlated with the recognition accuracy (%) in the explicit memory tasks with neutral and anxiety-inducing words, respectively. On the other hand, the WM volume of the PrG was negatively correlated with the reaction time in the same memory tasks. Conclusion This study demonstrated the regional volume changes on whole-brain GM and WM and the correlation between the brain structural alteration and explicit memory dysfunction in GAD patients. These findings would be helpful to understand the association between the brain structure abnormality and the functional deficit in the explicit memory in GAD.