title: Insular and hippocampal gray matter volume reductions in patients with major depressive disorder.
abstract: BACKGROUND
  Major depressive disorder is a serious psychiatric illness with a highly variable and heterogeneous clinical course. Due to the lack of consistent data from previous studies, the study of morphometric changes in major depressive disorder is still a major point of research requiring additional studies. The aim of the study presented here was to characterize and quantify regional gray matter abnormalities in a large sample of clinically well-characterized patients with major depressive disorder.
  
  
  METHODS
  For this study one-hundred thirty two patients with major depressive disorder and 132 age- and gender-matched healthy control participants were included, 35 with their first episode and 97 with recurrent depression. To analyse gray matter abnormalities, voxel-based morphometry (VBM8) was employed on T1 weighted MRI data. We performed whole-brain analyses as well as a region-of-interest approach on the hippocampal formation, anterior cingulate cortex and amygdala, correlating the number of depressive episodes.
  
  
  RESULTS
  Compared to healthy control persons, patients showed a strong gray-matter reduction in the right anterior insula. In addition, region-of-interest analyses revealed significant gray-matter reductions in the hippocampal formation. The observed alterations were more severe in patients with recurrent depressive episodes than in patients with a first episode. The number of depressive episodes was negatively correlated with gray-matter volume in the right hippocampus and right amygdala.
  
  
  CONCLUSIONS
  The anterior insula gray matter structure appears to be strongly affected in major depressive disorder and might play an important role in the neurobiology of depression. The hippocampal and amygdala volume loss cumulating with the number of episodes might be explained either by repeated neurotoxic stress or alternatively by higher relapse rates in patients showing hippocampal atrophy.
authors: Department of Psychiatry, University of Marburg, Marburg, Germany.
authors: Mirjam
authors: M
authors: Stratmann
authors: Department of Psychiatry, University of Marburg, Marburg, Germany.
authors: Carsten
authors: C
authors: Konrad
authors: Department of Clinical Radiology, University of Münster, Münster, Germany.
authors: Harald
authors: H
authors: Kugel
authors: Department of Psychiatry, University of Marburg, Marburg, Germany.
authors: Axel
authors: A
authors: Krug
authors: Department of Psychiatry, University of Münster, Münster, Germany.
authors: Sonja
authors: S
authors: Schöning
authors: Department of Psychiatry, University of Münster, Münster, Germany.
authors: Patricia
authors: P
authors: Ohrmann
authors: Department of Psychiatry, University of Münster, Münster, Germany.
authors: Christina
authors: C
authors: Uhlmann
authors: Department of Psychiatry, University of Münster, Münster, Germany; Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, University of Münster, Münster, Germany.
authors: Christian
authors: C
authors: Postert
authors: Department of Psychosomatic Medicine and Psychotherapy, University of Leipzig, Leipzig, Germany.
authors: Thomas
authors: T
authors: Suslow
authors: Department of Clinical Radiology, University of Münster, Münster, Germany.
authors: Walter
authors: W
authors: Heindel
authors: Department of Psychiatry, University of Münster, Münster, Germany.
authors: Volker
authors: V
authors: Arolt
authors: Department of Psychiatry, University of Marburg, Marburg, Germany.
authors: Tilo
authors: T
authors: Kircher
authors: Department of Psychiatry, University of Marburg, Marburg, Germany; Department of Psychiatry, University of Münster, Münster, Germany.
authors: Udo
authors: U
authors: Dannlowski
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003865:Major Depressive Disorder / Q000473:pathology*; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D055815:Young Adult