title: Thinner Medial Temporal Cortex in Adolescents With Attention-Deficit/Hyperactivity Disorder and the Effects of Stimulants.
abstract: OBJECTIVE
  Attention-deficit/hyperactivity disorder (ADHD) has been associated with widespread changes in cortical thickness (CT). Findings have been inconsistent, however, possibly due to age differences between samples. Cortical changes have also been suggested to be reduced or to disappear with stimulant treatment. We investigated differences in CT between adolescents/young adults with and without ADHD in the largest ADHD sample to date, the NeuroIMAGE sample. Second, we investigated how such differences were related to age and stimulant treatment.
  
  
  METHODS
  Participants (participants with ADHD = 306; healthy controls = 184, 61% male, 8-28 years of age, mean age = 17 years) underwent structural magnetic resonance imaging. Participants and pharmacies provided detailed information regarding lifetime stimulant treatment, including cumulative intake and age of treatment initiation and cessation. Vertexwise statistics were performed in Freesurfer, modeling the main effect of diagnosis on CT and its interaction with age. Effects of stimulant treatment parameters on CT were modeled within the sample with ADHD.
  
  
  RESULTS
  After correction for multiple comparisons, participants with ADHD showed decreased medial temporal CT in both left (pCLUSTER = .008) and right (pCLUSTER = .038) hemispheres. These differences were present across different ages and were associated with symptoms of hyperactivity and prosocial behavior. There were no age-by-diagnosis interaction effects. None of the treatment parameters predicted CT within ADHD.
  
  
  CONCLUSIONS
  Individuals with ADHD showed thinner bilateral medial temporal cortex throughout adolescence and young adulthood compared to healthy controls. We found no association between CT and stimulant treatment. The cross-sectional design of the current study warrants cautious interpretation of the findings.
authors.affiliation: University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: l.j.s.schweren@umcg.nl.
authors.forename: Lizanne J S
authors.initials: LJ
authors.lastname: Schweren
authors.affiliation: University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Catharina A
authors.initials: CA
authors.lastname: Hartman
authors.affiliation: VU University Amsterdam, The Netherlands.
authors.forename: Dirk J
authors.initials: DJ
authors.lastname: Heslenfeld
authors.affiliation: University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Dennis
authors.initials: D
authors.lastname: van der Meer
authors.affiliation: Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
authors.forename: Barbara
authors.initials: B
authors.lastname: Franke
authors.affiliation: VU University Amsterdam, The Netherlands.
authors.forename: Jaap
authors.initials: J
authors.lastname: Oosterlaan
authors.affiliation: Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands; Karakter Child and Adolescent Psychiatry University Centre Nijmegen.
authors.forename: Jan K
authors.initials: JK
authors.lastname: Buitelaar
authors.affiliation: State University of New York Upstate Medical University, Syracuse, New York.
authors.forename: Stephen V
authors.initials: SV
authors.lastname: Faraone
authors.affiliation: University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: Pieter J
authors.initials: PJ
authors.lastname: Hoekstra
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001289:Attention Deficit Disorder with Hyperactivity / Q000188:drug therapy / Q000473:pathology*; D016022:Case-Control Studies; D000697:Central Nervous System Stimulants / Q000627:therapeutic use*; D002648:Child; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D059906:Neuroimaging; D013702:Temporal Lobe / Q000187:drug effects / Q000473:pathology*; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants
keywords: ADHD; MRI; cortical thickness; long-term effects; stimulant treatment