Localized gray matter volume abnormalities in generalized anxiety disorder.

Generalized anxiety disorder (GAD) is characterized by excessive and persistent worrying. Neural substrates of this disorder are insufficiently understood, which relates to functional as well as to structural brain abnormalities. Especially, findings on the neuroanatomy of GAD have been inconsistent and were predominantly derived from pediatric samples. Therefore, we studied adult patients. Thirty-one women (16 patients with GAD and 15 healthy control participants) underwent structural MRI scanning. Gray matter volumes for specific brain regions involved in worrying, anticipatory anxiety, and emotion regulation were analyzed by means of voxel-based morphometry. Relative to controls, patients with GAD had larger volumes of the amygdala and the dorsomedial prefrontal cortex (DMPFC). Moreover, patients' self-reports on symptom severity were positively correlated with volumes of the DMPFC and the anterior cingulate cortex. Patients with GAD show localized gray matter volume differences in brain regions associated with anticipatory anxiety and emotion regulation. This abnormality may represent either a predisposition for GAD or a consequence of disorder-specific behavior, such as chronic worrying. This issue should be addressed in future MRI studies.