title: Toward Defining the Neural Substrates of ADHD: A Controlled Structural MRI Study in Medication-Naïve Adults.
abstract: OBJECTIVE
  We assessed the neural correlates of adult ADHD in treatment-naïve participants, an approach necessary for identifying neural substrates unconfounded by medication effects.
  
  
  METHODS
  The sample consisted of 24 medication-naïve adults with Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) diagnosed ADHD and 24 healthy controls, comparable on age, sex, handedness, reading achievement, IQ, and psychiatric comorbidity. All participants were assessed with structured diagnostic interviews. Magnetic resonance imaging (MRI)-based regional voxel-based morphometry (r-VBM) was used to assess volumetric differences in a priori defined brain regions of interest.
  
  
  RESULTS
  VBM analysis revealed group differences in the hypothesized cortical and subcortical areas; however, only cerebellar volume reductions in ADHD retained significance (p < .05) after corrections for multiple comparisons.
  
  
  CONCLUSIONS
  These results support the notion that medication-naïve ADHD as expressed in adulthood, manifests subtle brain volume reductions from normal in the cerebellum, and possibly in other syndrome-congruent gray-matter structures. Larger samples are required to confirm these findings.
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA nikos@cma.mgh.harvard.edu.
authors.forename: Nikos
authors.initials: N
authors.lastname: Makris
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA.
authors.forename: Lichen
authors.initials: L
authors.lastname: Liang
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Biederman
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA.
authors.forename: Eve M
authors.initials: EM
authors.lastname: Valera
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA.
authors.forename: Ariel B
authors.initials: AB
authors.lastname: Brown
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA.
authors.forename: Carter
authors.initials: C
authors.lastname: Petty
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Spencer
authors.affiliation: SUNY Upstate Medical University, Syracuse, NY, USA.
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Faraone
authors.affiliation: Massachusetts General Hospital, Boston, MA, USA Harvard Medical School, Boston, MA, USA Beth Israel Deaconess Medical Center, Boston, MA, USA.
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Seidman
mesh_terms: D000293:Adolescent; D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology* / Q000523:psychology; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D002531:Cerebellum / Q000473:pathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000473:pathology*; D055815:Young Adult
keywords: ADHD; VBM; brain structure; cerebellum; treatment-naïve ADHD