ADHD Research Today is a free monthly online journal that collates and summarizes the latest research about ADHD, including details on attention-deficit hyperactivity disorder, drugs, treatment, symptoms. | ||||||||
|
Inhibition of motor responses in siblings concordant and discordant for attention deficit hyperactivity disorder.Schachar RJ, Crosbie J, Barr CL, Ornstein TJ, Kennedy J, Malone M, Roberts W, Ickowicz A, Tannock R, Chen S, Pathare T Department of Psychiatry, The Hospital for Sick Children, University of Toronto, Toronto M5N 2L1, Canada. russell.schachar@sickkids.ca OBJECTIVE: The authors sought to determine whether nonaffected siblings of ADHD probands have a motor response inhibition deficit and to assess concordance for this inhibition deficit in ADHD-concordant and ADHD-discordant sibling pairs. METHOD: ADHD-concordant pairs (21 probands and their affected siblings), ADHD-discordant pairs (18 probands and their nonaffected siblings), and a group of unrelated, demographically balanced, healthy individuals (N=24) were compared on measures of response inhibition, ADHD behavior, impairment, and environmental risk. RESULTS: Concordant-pair probands, their affected siblings, and discordant-pair probands exhibited inhibitory control impairment relative to healthy comparison subjects. The performance of nonaffected siblings was intermediate between that of ADHD children and the healthy comparison subjects. Group differences persisted after age was controlled, and performance was not correlated with the number of ADHD symptoms. In ADHD-concordant sibling pairs, there was a significant relationship between proband and sibling inhibition deficit. In ADHD-discordant sibling pairs, inhibition deficit was evident in half of the nonaffected siblings of probands with an inhibition deficit. Groups did not differ in exposure to environmental risks. CONCLUSIONS: Impaired inhibitory control aggregates in the family members of individuals with ADHD and may serve as an indicator of genetic vulnerability to the disorder. Published 2 June 2005 in Am J Psychiatry, 162(6): 1076-82.
© 2004-2008 ADHD Research Today. All Rights Reserved. |
| ||||||
