Psychological Medicine

Original Articles

White-matter abnormalities in the right posterior hemisphere in generalized anxiety disorder: a diffusion imaging study

P. Brambillaa1a2 c1, G. Comoa3, M. Isolaa3, F. Tabogaa1, R. Zuliania1, S. Goljevsceka1, M. Ragognaa1, G. Brondania3, M. Baianoa4, L. Perinia1, A. Ferroa5, M. Bazzocchia3, C. Zuiania3 and M. Balestrieria1

a1 Department of Experimental Clinical Medical Sciences, Inter-University Centre for Behavioural Neurosciences, University of Udine, Udine, Italy

a2 Scientific Institute IRCCS ‘E. Medea’, Udine, Italy

a3 Department of Medical and Biological Sciences, University of Udine, Udine, Italy

a4 Centre for Weight and Eating Disorders, Portogruaro, Venice, Italy

a5 Department of Public Health and Community Medicine, Section of Psychiatry and Clinical Psychology, Inter-University Centre for Behavioural Neurosciences, University of Verona, Verona, Italy

Abstract

Background Prior imaging studies have shown structural, functional and biochemical impairments in patients with generalized anxiety disorder (GAD), particularly in the right hemisphere. In this study we investigated, for the first time to the best of our knowledge, the white-matter microstructure organization in GAD.

Method A total of 12 patients with DSM-IV GAD and 15 matched healthy controls underwent a magnetic resonance imaging session of diffusion weighted imaging, exploring white-matter water molecules by the means of apparent diffusion coefficients (ADCs). Regions of interests were placed in the frontal, parietal, temporal and occipital lobes and in the splenium and genu of the corpus callosum, bilaterally.

Results ADC measures were significantly greater in patients with GAD in the right splenium and right parietal cortex compared with healthy controls (p≤0.002). No significant correlations between ADCs and age or clinical variables were found.

Conclusions We provide evidence that GAD is associated with disrupted white-matter coherence of posterior right hemisphere regions, which may partly sustain the impaired cognitive regulation of anxiety. Future diffusion imaging investigations are expected to better elucidate the communication between the parietal cortex and other right hemisphere regions in sustaining the cognitive processing of social and emotional stimuli in patients with GAD.

(Received December 30 2010)

(Revised June 22 2011)

(Accepted June 23 2011)

(Online publication July 25 2011)

Correspondence

c1 Address for correspondence: P. Brambilla, Dipartimento di Scienze Mediche Sperimentali e Cliniche, Università di Udine, P.Le Kolbe N.3, 33110 Udine, Italy. (Email: paolo.brambilla@uniud.it)

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