High-field MRS study of GABA, glutamate and glutamine in social anxiety disorder: Response to treatment with levetiracetam

Objective: Abnormalities in brain gamma-aminobutyric acid (GABA) and glutamate may be relevant to the underlying pathophysiology of anxiety disorders including social anxiety disorder (SAD). Methods: We used proton magnetic resonance spectroscopy (pMRS) to examine whole brain and regional GABA, glutamate and glutamine in patients (N = 10) with SAD at baseline compared to a matched group of healthy controls (HC), and changes following 8 weeks of pharmacotherapy with levetiracetam. Results: For SAD subjects, there were significantly higher whole brain levels of glutamate and glutamine, though no significant differences in GABA. In the thalamus, glutamine was higher and GABA lower for SAD subjects. There was a significant reduction in thalamic glutamine with levetiracetam treatment. Conclusion: Our findings provide preliminary support for impaired GABAergic and overactive glutamatergic function in social anxiety disorder and the potential relevance of changes in these systems for the anxiolytic response to levetiracetam. (C) 2007 Elsevier Inc. All fights reserved.