title: Shared microstructural features of behavioral and substance addictions revealed in areas of crossing fibers.
abstract: BACKGROUND
  Similarities between behavioral and substance addictions exist. However, direct neurobiological comparison between addictive disorders is rare. Determination of disorder-specificity (or lack thereof) of alterations within white-matter microstructures will advance understanding of the pathophysiology of addictions.
  
  
  METHODS
  We compared white-matter microstructural features between individuals with gambling disorder (GD; n=38), cocaine-use disorder (CUD; n=38) and healthy comparison (HC; n=38) participants, as assessed using diffusion-weighted magnetic resonance imaging (dMRI). To provide a more precise estimate of diffusion within regions of complex architecture (e.g., cortico-limbic tracts), analyses were conducted using a crossing-fiber model incorporating local-orientation modeling (tbss_x). Anisotropy estimates for primary and secondary fiber orientations were compared using ANOVAs corrected for multiple comparisons across space using threshold-free cluster enhancement (pFWE<.05).
  
  
  RESULTS
  A main effect of group on anisotropy of secondary fiber orientations within the left internal capsule, corona radiata, forceps major and posterior thalamic radiation, involving reduced anisotropy among GD and CUD participants in comparison to HC participants. No differences in anisotropy measures were found between GD and CUD individuals.
  
  
  CONCLUSIONS
  This is the first study to compare diffusion indices directly between behavioral and substance addictions and the largest dMRI study of GD. Our findings indicate similar white-matter microstructural alterations across addictions that cannot be attributed solely to exposure to drugs or alcohol and thus may be a vulnerability mechanism for addictive disorders.
authors.affiliation: CASAColumbia, Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Sarah W
authors.initials: SW
authors.lastname: Yip
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Kristen P
authors.initials: KP
authors.lastname: Morie
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Jiansong
authors.initials: J
authors.lastname: Xu
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: R Todd
authors.initials: RT
authors.lastname: Constable
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Connecticut Mental Health Center, New Haven, CT, USA.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Malison
authors.affiliation: Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Kathleen M
authors.initials: KM
authors.lastname: Carroll
authors.affiliation: CASAColumbia, Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Connecticut Mental Health Center, New Haven, CT, USA; Department of Neurobiology, Yale University School of Medicine, New Haven, CT, USA; Yale Child Study Center, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Marc N
authors.initials: MN
authors.lastname: Potenza
keywords: alcohol-use disorder; behavioral addiction; diffusion tensor imaging (DTI); impulsivity; pathological gambling; substance-use disorder