Dorsolateral Prefrontal Cortical Pathology in Generalized Anxiety Disorder: A Proton Magnetic Resonance Spectroscopic Imaging Study

OBJECTIVE: Few neuroimaging studies of generalized anxiety disorder have been conducted. The present study used proton magnetic resonance spectroscopy to assess concentrations of N-acetylaspartate, often considered a marker of neuronal viability, in generalized anxiety disorder patients. METHOD: N-Acetylaspartate/creatine resonance ratios were measured in the left and right dorsolateral prefrontal cortex and hippocampus of 15 medication-free generalized anxiety disorder patients and 15 age- and sex-matched healthy volunteers. RESULTS: Generalized anxiety disorder patients had a 16.5% higher N-acetylaspartate/creatine ratio in the right dorsolateral prefrontal cortex compared with healthy participants; 13 of 15 matched patient-comparison subject pairs displayed a difference in this direction. In addition, generalized anxiety disorder patients reporting childhood abuse had lower N-acetylaspartate/creatine ratios in the right dorsolateral prefrontal cortex than did nonabused patients. Metabolite differences were not detected in other regions. CONCLUSIONS: Generalized anxiety disorder is associated with asymmetric increases in the N-acetylaspartate/creatine ratio, a suggested marker of neuronal viability, in the prefrontal cortex. The findings also support prior research linking childhood abuse to reduced neuronal viability.