title: A COMPREHENSIVE EXAMINATION OF WHITE MATTER TRACTS AND CONNECTOMETRY IN MAJOR DEPRESSIVE DISORDER.
abstract: BACKGROUND
  Major depressive disorder (MDD) is a debilitating disorder characterized by widespread brain abnormalities. The literature is mixed as to whether or not white matter abnormalities are associated with MDD. This study sought to examine fractional anisotropy (FA) in white matter tracts in individuals with MDD using diffusion tensor imaging (DTI).
  
  
  METHODS
  139 participants with MDD and 39 healthy controls (HC) in a multisite study were included. DTI scans were acquired in 64 directions and FA was determined in the brain using four methods: region of interest (ROI), tract-based spatial statistics (TBSS), and diffusion tractography. Diffusion connectometry was used to identify white matter pathways associated with MDD.
  
  
  RESULTS
  There were no significant differences when comparing FA in MDD and HC groups using any method. In the MDD group, there was a significant relationship between depression severity and FA in the right medial orbitofrontal cortex, and between age of onset of MDD and FA in the right caudal anterior cingulate cortex using the ROI method. There was a significant relationship between age of onset and connectivity in the thalamocortical radiation, inferior longitudinal fasciculus, and cerebellar tracts using diffusion connectometry.
  
  
  CONCLUSIONS
  The lack of group differences in FA and connectometry analysis may result from the clinically heterogenous nature of MDD. However, the relationship between FA and depression severity may suggest a state biomarker of depression that should be investigated as a potential indicator of response. Age of onset may also be a significant clinical feature to pursue when studying white matter tracts.
authors.affiliation: Department of Psychiatry, Stony Brook University, Stony Brook, New York.
authors.forename: Doreen M
authors.initials: DM
authors.lastname: Olvet
authors.affiliation: Department of Psychology, Stony Brook University, Stony Brook, New York.
authors.forename: Lauren
authors.initials: L
authors.lastname: Delaparte
authors.affiliation: Department of Psychology, Carnegie Mellon University, Pittsburgh, Pittsburgh.
authors.forename: Fang-Cheng
authors.initials: FC
authors.lastname: Yeh
authors.affiliation: Department of Psychiatry, Stony Brook University, Stony Brook, New York.
authors.forename: Christine
authors.initials: C
authors.lastname: DeLorenzo
authors.affiliation: Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: McGrath
authors.affiliation: Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York.
authors.forename: Myrna M
authors.initials: MM
authors.lastname: Weissman
authors.affiliation: Department of Psychiatry, New York State Psychiatric Institute, Columbia University College of Physicians and Surgeons, New York, New York.
authors.forename: Phillip
authors.initials: P
authors.lastname: Adams
authors.affiliation: Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Fava
authors.affiliation: Department of Psychiatry, Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Thilo
authors.initials: T
authors.lastname: Deckersbach
authors.affiliation: Department of Psychiatry, University of Michigan School of Medicine, Ann Arbor, Michigan.
authors.forename: Melvin G
authors.initials: MG
authors.lastname: McInnis
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Carmody
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Crystal M
authors.initials: CM
authors.lastname: Cooper
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Benji T
authors.initials: BT
authors.lastname: Kurian
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Hanzhang
authors.initials: H
authors.lastname: Lu
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Marisa S
authors.initials: MS
authors.lastname: Toups
authors.affiliation: Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas.
authors.forename: Madhukar H
authors.initials: MH
authors.lastname: Trivedi
authors.affiliation: Department of Psychiatry, Stony Brook University, Stony Brook, New York.|Department of Radiology, Stony Brook University, Stony Brook, New York.
authors.forename: Ramin V
authors.initials: RV
authors.lastname: Parsey
mesh_terms: D000328:Adult; D016880:Anisotropy; D063132:Connectome; D003865:Major Depressive Disorder / Q000473:pathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D066127:White Matter / Q000473:pathology*
keywords: brain imaging/neuroimaging; connectometry, fractional anisotropy; depression; diffusion tensor imaging; mood disorders; multisite study; white matter tracts