Temperament and character profiles and the dopamine D4 receptor gene in ADHD.
OBJECTIVE
This study was designed to investigate the link among attention deficit hyperactivity disorder (ADHD) in adults, novelty-seeking temperament, and the 48-base pair (bp) dopamine D4 receptor (DRD4) gene variant.


METHODS
This study drew from a larger molecular genetic study of ADHD in which the ascertainment criterion was having an affected sibling pair with ADHD. Parents (N=171) from 96 families provided data. Of the 171 parents, 56 (33%) had a lifetime history of ADHD, with 28 (50%) continuing to meet DSM-IV criteria (i.e., "persistent" ADHD). Latent variable modeling was used to test whether the DRD4 gene variant or Temperament and Character Inventory factors could predict ADHD.


RESULTS
Using latent variable modeling, the authors were able to confirm the first-order factor structure of the Temperament and Character Inventory. Furthermore, novelty seeking predicted ADHD lifetime diagnosis (R(2)=26%), while the DRD4 gene variant independently predicted ADHD (R(2)=5%) but not novelty seeking.


CONCLUSIONS
In this unique sample of parents from multiply affected ADHD families, novelty seeking and the 48-bp DRD4 variant were associated with a lifetime history of ADHD. However, the association between novelty seeking and ADHD does not appear to be due to variation in the 48-bp DRD4 variant.
Lynn
Deborah E
DE
UCLA Department of Child and Adolescent Psychiatry, 10850 Wilshire Blvd., Suite 200, Los Angeles, CA 90024, USA. deborah.lynn@verizon.net
Lubke
Gitta
G
Yang
May
M
McCracken
James T
JT
McGough
James J
JJ
Ishii
Janeen
J
Loo
Sandra K
SK
Nelson
Stanley F
SF
Smalley
Susan L
SL
D000328:Adult; D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D002605:Character; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005106:Exploratory Behavior / Q000502:physiology; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease; D014644:Genetic Variation; D006801:Humans; D008297:Male; D010375:Pedigree; D010555:Personality Inventory; D011110:Polymorphism, Genetic; D011569:Psychiatric Status Rating Scales; D017448:Receptors, Dopamine D2 / Q000235:genetics* / Q000502:physiology; D050638:Receptors, Dopamine D4; D013694:Temperament / Q000145:classification / Q000502:physiology*
C493599:DRD4 protein, human; D005819:Genetic Markers; D017448:Receptors, Dopamine D2; D050638:Receptors, Dopamine D4