title: Disorder-specific grey matter deficits in attention deficit hyperactivity disorder relative to autism spectrum disorder.
abstract: BACKGROUND
  Attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD) are two common childhood disorders that exhibit genetic and behavioural overlap and have abnormalities in similar brain systems, in particular in frontal and cerebellar regions. This study compared the two neurodevelopmental disorders to investigate shared and disorder-specific structural brain abnormalities.
  
  
  METHODS
  Forty-four predominantly medication-naïve male adolescents with ADHD, 19 medication-naïve male adolescents with ASD and 33 age-matched healthy male controls were scanned using high-resolution T1-weighted volumetric imaging in a 3-T magnetic resonance imaging (MRI) scanner. Voxel-based morphometry (VBM) was used to test for group-level differences in structural grey matter (GM) and white matter (WM) volumes.
  
  
  RESULTS
  There was a significant group difference in the GM of the right posterior cerebellum and left middle/superior temporal gyrus (MTG/STG). Post-hoc analyses revealed that this was due to ADHD boys having a significantly smaller right posterior cerebellar GM volume compared to healthy controls and ASD boys, who did not differ from each other. ASD boys had a larger left MTG/STG GM volume relative to healthy controls and at a more lenient threshold relative to ADHD boys.
  
  
  CONCLUSIONS
  The study shows for the first time that the GM reduction in the cerebellum in ADHD is disorder specific relative to ASD whereas GM enlargement in the MTG/STG in ASD may be disorder specific relative to ADHD. This study is a first step towards elucidating disorder-specific structural biomarkers for these two related childhood disorders.
authors.affiliation: Department of Child and Adolescent Psychiatry,Institute of Psychiatry,King's College London,UK.
authors.forename: L
authors.initials: L
authors.lastname: Lim
authors.affiliation: Department of Child and Adolescent Psychiatry,Institute of Psychiatry,King's College London,UK.
authors.forename: K
authors.initials: K
authors.lastname: Chantiluke
authors.affiliation: Department of Child and Adolescent Psychiatry,Institute of Psychiatry,King's College London,UK.
authors.forename: A I
authors.initials: AI
authors.lastname: Cubillo
authors.affiliation: Department of Child and Adolescent Psychiatry,Institute of Psychiatry,King's College London,UK.
authors.forename: A B
authors.initials: AB
authors.lastname: Smith
authors.affiliation: Department of Neuroimaging,Institute of Psychiatry, King's College London,UK.
authors.forename: A
authors.initials: A
authors.lastname: Simmons
authors.affiliation: Department of Neuroimaging,Institute of Psychiatry, King's College London,UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Mehta
authors.affiliation: Department of Child and Adolescent Psychiatry,Institute of Psychiatry,King's College London,UK.
authors.forename: K
authors.initials: K
authors.lastname: Rubia
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000473:pathology*; D000067877:Autism Spectrum Disorder / Q000473:pathology*; D016022:Case-Control Studies; D002531:Cerebellum / Q000473:pathology*; D002648:Child; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D008297:Male; D009929:Organ Size; D013702:Temporal Lobe / Q000473:pathology*; D066127:White Matter / Q000473:pathology*
keywords: voxel-based morphometry