Different white matter abnormalities between the first-episode, treatment-naive patients with posttraumatic stress disorder and generalized anxiety disorder without comorbid conditions

Background: This study compared brain white matter integrity in two groups of patients with DSM-IV anxiety disorders. Method: Seventeen patients with posttraumatic stress disorder (PTSD), 20 with generalized anxiety disorder (GAD), and 28 healthy controls were assessed on diffusion tensor imaging. Results: As compared to healthy controls, increased fractional anisotropy (FA) in left superior frontal gyrus in PTSD patients, and increased FA in right postcentral gyrus in GAD subjects were exhibited. Furthermore, patients with PTSD showed reduced FA in right anterior cingulate gyrus relative to GAD subjects. However, there was no significant correlation between the FA value of any altered region and the severity of FTSD or GAD. Limitations: The sample studied can be considered small. Gender and educational level were not well-matched among the groups. Conclusions: We tentatively speculate that abnormal white matter integrity of right anterior cingulate gyrus is an important neuroimaging marker of PTSD that distinguishes it from other anxiety disorders such as GAD. (C) 2011 Elsevier B.V. All rights reserved.