Gwang-Won Kim1, Chung-Man Moon1, Tae-Hoon Kim1, and Gwang-Woo Jeong1,2
1Research Institute of Medical Imaging, Chonnam National University Medical School, Gwang-ju, Korea, Republic of, 2Department of Radiology, Chonnam National University Medical School, Gwang-ju, Korea, Republic of
Synopsis
Obsessive
compulsive disorder (OCD) and generalized anxiety disorder (GAD) are associated
with abnormalities in the processing and regulation of anxiety. The purpose of
this study was to evaluate gray matter (GM) and white matter (WM) volume
alterations over whole-brain structures in healthy controls vs. patients with
OCD vs. GAD using voxel-based morphometry (VBM), and further to assess the
correlations of the GM and WM volume variations with the scores for anxiety
severity in OCD and GAD.Subjects and methods
Sixteen patients with OCD (mean age = 31.3±10.2 years), 16 patients with GAD (33.0±8.6 years), and 16 healthy controls (32.5±7.3) participated in this study (Table 1). The patients with OCD were assessed using the Clinical Global Impression-Severity Scale (CGI-S), Hamilton Rating Scale for Anxiety (HAM-A), Hamilton Rating Scale for Depression (HAM-D), and Yale-Brown Obsessive Compulsive Scale (Y-BOCS) (Table 1). The patients with GAD were assessed using the CGI-S, HAM-A, HAM-D, Anxiety Sensitivity Index-Revised (ASI-R), and Generalized Anxiety Disorder Scale 7 (GAD-7) (Table 1). Magnetic resonance examination was performed on a 3.0-T Magnetom Verio MR Scanner (Siemens Medical Solutions, Erlangen, Germany) with a 12-channel birdcage head coil. The T1-weighted sagittal images were acquired using a three-dimensional magnetization prepared rapid acquisition gradient echo (3D-MPRAGE) pulse sequence with the following parameters: repetition time/echo time = 1900 ms/2.35 ms, field of view = 220×220 mm2, matrix = 256×256, slice thickness = 1 mm, and slices = 176. MRI data were post-processed using Statistical Parametric Mapping software (SPM8) with the diffeomorphic anatomical registration through an exponentiated Lie algebra (DARTEL) algorithm.
Results and discussion
To our knowledge, this is the first study to evaluate the GM and WM volume abnormalities between patients with OCD and GAD using DARTEL-based VBM. The main findings were as follows: (1) patients with OCD showed GM atrophy in the anterior cingulate cortex (ACC), orbitofrontal gyrus (OFG), superior temporral gyrus (STG), and angular gyrus (AG) compared with healthy controls (Table 2, Fig. 1); (2) patients with GAD showed GM atrophy in the ACC, superior occipital gyrus (SOG), precuneus, OFG, dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (mPFC), superior temporal gyrus (STG), insula, and AG, and WM atrophy in the DLPFC, mPFC, and OFG compared with healthy controls (Table 2, Fig. 1); (3) compared with patients with OCD, patients with GAD showed GM atrophy in the SOG and mPFC, and showed WM atrophy in the mPFC and AG (Table 2, Fig. 2); and (4) GM and WM volumes of the mPFC and DLPFC in patients with GAD were negatively correlated with HAM-A scores (Fig. 3).
Conclusion
Our findings indicate that morphometric deviation of the mPFC in patients with GAD may be associated with anxiety disorder. This study will be useful to understand the neuropathology of OCD and GAD in terms of GM and WM abnormalities.
Acknowledgements
This
research was supported by the National Research Foundation of Korea (NRF)
grants funded by the Korea government (MSIP) (2015R1A2A2A01007827) and the
Ministry of Education (2014R1A1A2006730).References
1. Moon et al, Neuroreport.
2014;25:184-189
2. Park and Jeong, Psychiatry Clin Neurosci 2015;69:717-723