title: Confirmation of an inhibitory control deficit in attention-deficit/hyperactivity disorder.
abstract: The objective of this study was to determine whether deficient inhibitory control distinguishes children with a diagnosis of attention-deficit/hyperactivity (ADHD) disorder, conduct disorder (CD), and comorbid ADHD + CD from normally developing children. Participants were rigorously diagnosed children (age 7 to 12 years) with ADHD (N = 72), CD (N = 13) or ADHD + CD (N = 47) and 33 control children (NC). We studied inhibitory control using the stop-signal paradigm, a laboratory task that assessed the ability to inhibit an ongoing action. The ADHD group had significantly impaired inhibitory control compared to NC, CD, and ADHD + CD children. These results indicate that children with ADHD have deficient inhibition as measured in the stop-signal paradigm and that ADHD occurring in the presence of ADHD + CD may represent a phenocopy of CD rather than a variant of ADHD.
authors.affiliation: Department of Psychiatry and the Brain and Behavior Program, The Hospital for Sick Children and the University of Toronto, Ontario, Canada. russell.schachar@sickkids.on.ca
authors.forename: R
authors.initials: R
authors.lastname: Schachar
authors.forename: V L
authors.initials: VL
authors.lastname: Mota
authors.forename: G D
authors.initials: GD
authors.lastname: Logan
authors.forename: R
authors.initials: R
authors.lastname: Tannock
authors.forename: P
authors.initials: P
authors.lastname: Klim
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000523:psychology*; D016022:Case-Control Studies; D002648:Child; D015897:Comorbidity; D019955:Conduct Disorder / Q000523:psychology*; D005260:Female; D006801:Humans; D007266:Inhibition, Psychological; D008297:Male; D013647:Task Performance and Analysis