title: Differential reward processing in subtypes of adult attention deficit hyperactivity disorder.
abstract: OBJECTIVE
  Abnormalities in reward processing have been found in adolescents and adults with ADHD using the 'Monetary Incentive Delay' (MID) task. However, ADHD groups in previous studies were heterogeneous regarding ADHD subtype, gender and, in part, drug treatment status. This study sought to compare neural activations in the ventral striatum (VS) and prefrontal regions during reward processing in homogenous ADHD subtype groups and healthy adults, using the MID task.
  
  
  METHODS
  In total, 24 drug-naïve, right-handed male adults with ADHD (12 subjects with combined type (ADHD-ct) and 12 subjects with predominantly inattentive (ADHD-it) type ADHD), and twelve healthy right-handed male control subjects were included.
  
  
  RESULTS
  Compared to ADHD-ct and healthy subjects, ADHD-it subjects showed a bilateral ventral striatal deficit during reward anticipation. In contrast, ADHD-ct subjects showed orbitofrontal hyporesponsiveness to reward feedback when compared with ADHD-it and healthy subjects.
  
  
  CONCLUSIONS
  This is the first fMRI study that delineates dysfunctional and subtype-divergent neural and behavioural reward processing in adults with ADHD.
authors.affiliation: Dept. of Psychiatry, Ruhr-University Bochum, LWL University Hospital, Bochum, Alexandrinenstr. 1, 44791 Bochum, Germany.
authors.forename: Marc-Andreas
authors.initials: MA
authors.lastname: Edel
authors.forename: Björn
authors.initials: B
authors.lastname: Enzi
authors.forename: Henning
authors.initials: H
authors.lastname: Witthaus
authors.forename: Martin
authors.initials: M
authors.lastname: Tegenthoff
authors.forename: Sören
authors.initials: S
authors.lastname: Peters
authors.forename: Georg
authors.initials: G
authors.lastname: Juckel
authors.forename: Silke
authors.initials: S
authors.lastname: Lissek
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000145:classification / Q000150:complications* / Q000473:pathology / Q000523:psychology*; D001921:Brain / Q000098:blood supply / Q000473:pathology*; D007839:Functional Laterality; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007859:Learning Disabilities / Q000209:etiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009042:Motivation / Q000502:physiology*; D009483:Neuropsychological Tests; D010100:Oxygen / Q000097:blood; D011569:Psychiatric Status Rating Scales; D012201:Reward; D055815:Young Adult
chemical_list: D010100:Oxygen