title: Association of ADHD and conduct disorder--brain electrical evidence for the existence of a distinct subtype.
abstract: BACKGROUND
  To evaluate the impact of psychopathological comorbidity with oppositional defiant/conduct disorder (ODD/CD) on brain electrical correlates in children with attention deficit hyperactivity disorder (ADHD) and to study the pathophysiological background of comorbidity of ADHD+ODD/CD.
  
  
  METHODS
  Event-related potentials (ERPs) were recorded during a cued continuous performance test (CPT-A-X) in children (aged 8 to 14 years) with ICD-10 diagnoses of either hyperkinetic disorder (HD; n = 15), hyperkinetic conduct disorder (HCD; n = 16), or ODD/CD (n = 15) and normal children (n = 18). HD/HCD diagnoses in all children were fully concordant with the DSM-IV diagnosis of ADHD-combined type. ERP-microstates, i.e., time segments with stable brain electrical map topography were identified by adaptive segmentation. Their characteristic parameters and behavioral measures were further analyzed.
  
  
  RESULTS
  Children with HD but not comorbid children showed slower and more variable reaction times compared to control children. Children with HD and ODD/CD-only but not comorbid children displayed reduced P3a amplitudes to cues and certain distractors (distractor-X) linked to attentional orienting. Correspondingly, global field power of the cue-CNV microstate related to anticipation and preparation was reduced in HD but not in HCD. Topographical alterations of the HD occurred already in the cue-P2/N2 microstate. In sum, the comorbid group was less deviant than both the HD-group and the ODD/CD-group.
  
  
  CONCLUSIONS
  The findings suggest that HD children (ADHD-combined type without ODD/CD) suffer from a more general deficit (e.g., suboptimal energetical state regulation) including deficits of attentional orienting and response preparation than just a responseinhibitory deficit, backing the hypothesis of an involvement of a dysregulation of the central noradrenergic networks. The results contradict the hypothesis that ADHD+ODD/CD represents an additive co-occurrence of ADHD and ODD/CD and strongly suggest that it represents a separate pathological entity as considered in the ICD-10 classification system, which differs from both HD and ODD/CD-only.
authors.affiliation: Child and Adolescent Psychiatry, University of Göttingen, Germany. tbanasc@gwdg.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Banaschewski
authors.forename: Daniel
authors.initials: D
authors.lastname: Brandeis
authors.forename: Hartmut
authors.initials: H
authors.lastname: Heinrich
authors.forename: Bjoern
authors.initials: B
authors.lastname: Albrecht
authors.forename: Edgar
authors.initials: E
authors.lastname: Brunner
authors.forename: Aribert
authors.initials: A
authors.lastname: Rothenberger
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology* / Q000503:physiopathology*; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000453:epidemiology* / Q000503:physiopathology*; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D002648:Child; D015897:Comorbidity; D019955:Conduct Disorder / Q000453:epidemiology* / Q000503:physiopathology*; D018913:Event-Related Potentials, P300; D005071:Evoked Potentials; D005858:Germany / Q000453:epidemiology; D006801:Humans; D009483:Neuropsychological Tests; D011930:Reaction Time