title: Deficient inhibition as a marker for familial ADHD.
abstract: OBJECTIVE
  The authors investigated whether deficient inhibitory control, as measured by the stop-signal paradigm, delineates a familial subgroup of attention deficit hyperactivity disorder (ADHD).
  
  
  METHODS
  Subjects were 54 ADHD children defined as having poor or good inhibition (on the basis of stop-signal paradigm performance) and 26 healthy comparison children. Family history of ADHD and measures of neurobiological and psychosocial risk were compared among the three groups.
  
  
  RESULTS
  ADHD was significantly more prevalent in the families of the children with ADHD who exhibited poor inhibition (48.1%) than in the families of those exhibiting good inhibition (18.5%) or in the families of healthy comparison children (7.7%). No differences in neurobiological or psychosocial risk were found for the three groups.
  
  
  CONCLUSIONS
  Deficient inhibition delineates a familial subtype of ADHD. Psychosocial and neurobiological factors did not account for inclusion in the good inhibition group and did not act conjointly with inhibition to increase the risk for ADHD in the poor inhibition group. This study demonstrates that cognitive measures such as a laboratory measure of inhibition can serve as phenotype markers for genetic analyses.
authors.affiliation: Department of Psychiatry and the Brain and Behavior Program at The Hospital for Sick Children, Toronto, Ontario, Canada.
authors.forename: J
authors.initials: J
authors.lastname: Crosbie
authors.forename: R
authors.initials: R
authors.lastname: Schachar
mesh_terms: D000704:Analysis of Variance; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics*; D002648:Child; D015897:Comorbidity; D019955:Conduct Disorder / Q000453:epidemiology; D004410:Dyslexia / Q000453:epidemiology; D005260:Female; D005819:Genetic Markers; D020022:Genetic Predisposition to Disease; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D011930:Reaction Time; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D005819:Genetic Markers