title: Not lesser but Greater fractional anisotropy in adolescents with alcohol use disorders.
abstract: OBJECTIVE
  The objective of this study is to examine white matter microstructure using diffusion tensor imaging (DTI) in a sample of adolescents with alcohol use disorders (AUD) and no psychiatric or substance co-morbidity.
  
  
  METHODS
  Fifty adolescents with AUD and fifty non-alcohol abusing controls matched on gender and age were studied with DTI, neurocognitive testing, and a clinical assessment that included measures of alcohol use and childhood trauma. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were computed, registered to a common template, and voxel-wise statistical analysis used to assess group differences. Associations between regions of altered WM microstructure and clinical or neurocognitive measures were also assessed.
  
  
  RESULTS
  Compared with controls, adolescent drinkers without co-morbid substance abuse or externalizing disorder, showed 1) no regions of significantly lower FA, 2) increased FA in WM tracts of the limbic system; 3) no MD differences; and 4) within the region of higher FA in AUD, there were no associations between FA and alcohol use, cognition, or trauma.
  
  
  CONCLUSIONS
  The most important observation of this study is our failure to observe significantly smaller FA in this relatively large alcohol abuse/dependent adolescent sample. Greater FA in the limbic regions observed in this study may index a risk for adolescent AUD instead of a consequence of drinking. Drinking behavior may be reinforced in those with higher FA and perhaps greater myelination in these brain regions involved in reward and reinforcement.
authors.affiliation: Neurobehavioral Research, Inc., Ala Mona Pacific Center, 1585 Kapiolani Blvd. Suite 1030, Honolulu, HI 95814, USA.
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Cardenas
authors.forename: David
authors.initials: D
authors.lastname: Greenstein
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Fouche
authors.forename: Helen
authors.initials: H
authors.lastname: Ferrett
authors.forename: Natalie
authors.initials: N
authors.lastname: Cuzen
authors.forename: Dan J
authors.initials: DJ
authors.lastname: Stein
authors.forename: George
authors.initials: G
authors.lastname: Fein
keywords: AUD, alcohol use disorders; Adolescents; Alcohol use disorders; DTI, diffusion tensor imaging; FA, fractional anisotropy; Fractional anisotropy; MD, mean diffusivity; Mean diffusivity; Voxel-wise analysis