Increased amygdalar and hippocampal volumes in young adults with social anxiety

PLoS One. 2014 Feb 11;9(2):e88523. doi: 10.1371/journal.pone.0088523. eCollection 2014.

Abstract

Background: Functional neuroimaging studies have consistently shown abnormal limbic activation patterns in socially anxious individuals, but structural data on the amygdala and hippocampus of these patients are scarce. This study explored the existence of structural differences in the whole brain, amygdala, and hippocampus of subjects with clinical and subthreshold social anxiety compared to healthy controls. We hypothesized that there would be volumetric differences across groups, without predicting their direction (i.e. enlargement or reduction).

Methods: Subjects classified as having social anxiety disorder (n = 12), subthreshold social anxiety (n = 12) and healthy controls (n = 14) underwent structural magnetic resonance imaging scans. The amygdala and hippocampus were defined a priori as regions of interest and volumes were calculated by manual tracing. Whole brain volume was calculated using voxel-based morphometry.

Results: The bilateral amygdala and left hippocampus were enlarged in socially anxious individuals relative to controls. The volume of the right hippocampus was enlarged in subthreshold social anxiety participants relative to controls. No differences were found across groups in respect to total brain volume.

Conclusions: Our results show amygdalar and hippocampal volume alterations in social anxiety, possibly associated with symptom severity. The time course of such alterations and the cellular and molecular bases of limbic plasticity in social anxiety should be further investigated.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Amygdala / pathology*
  • Anxiety Disorders / physiopathology*
  • Brain Mapping
  • Case-Control Studies
  • Female
  • Hippocampus / pathology*
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging
  • Male
  • Young Adult

Grants and funding

This research was supported by the National Institute for Translational Medicine (INCT-TM)(www.ufrgs.br/inct-tm) of the Brazilian Council for Scientific and Technological Development (CNPq) and by the Research Support Center for Applied Neuroscience (NAPNA)(www.napnausp.org.br) of the São Paulo Research Foundation (NAPNA). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.