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. 2007 Nov 1;62(9):991-8.
doi: 10.1016/j.biopsych.2007.04.003. Epub 2007 Jun 22.

Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder

L Cinnamon Bidwell  1 , Erik G Willcutt, John C Defries, Bruce F Pennington
Affiliations

Testing for neuropsychological endophenotypes in siblings discordant for attention-deficit/hyperactivity disorder

L Cinnamon Bidwell et al. Biol Psychiatry. .

Abstract

Background: Neurocognitive deficits associated with attention-deficit/hyperactivity disorder (ADHD) might be useful intermediate endophenotypes for determining specific genetic pathways that contribute to ADHD.

Methods: This study administered 17 measures from prominent neuropsychological theories of ADHD (executive function, processing speed, arousal regulation and, motivation/delay aversion) in dizygotic (DZ) twin pairs discordant for ADHD and control twin pairs (ages 8-18 years) to compare performance between twins affected with ADHD (n = 266), their unaffected co-twins (n = 228), and control children from twin pairs without ADHD or learning difficulties (n = 332).

Results: The ADHD subjects show significant impairment on executive function, processing speed, and response variability measures compared with control subjects. Unaffected co-twins of ADHD subjects are significantly impaired on nearly all the same measures as their ADHD siblings, even when subclinical symptoms of ADHD are controlled.

Conclusions: Executive function, processing speed, and response variability deficits might be useful endophenotypes for genetic studies of ADHD.

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References

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