Genetic and environmental influences on the relation between attention problems and attention deficit hyperactivity disorder.
OBJECTIVE
The assessment of symptoms of ADHD in children is usually based on a clinical interview or a behavior checklist. The aim of the present study is to investigate the extent to which these instruments measure an underlying construct and to estimate the genetic and environmental influences on individual differences in ADHD.


METHODS
Maternal ratings were collected on 10,916 twins from 5,458 families. Child Behavior Checklist (CBCL) ratings were available for 10,018, 6,565, and 5,780 twins at the ages 7, 10, and 12, respectively. The Conners Rating Scale (4,887 twins) and the DSM interview (1,006 twins) were completed at age 12. The magnitude of genetic and environmental influences on the variance of the three measures of ADHD and the covariance among the three measures of ADHD was obtained.


RESULTS
Phenotypic correlations range between .45 and .77. Variances and covariances of the measurements were explained mainly by genetic influences. The model that provided the best account of the data included an independent pathway for additive and dominant genetic effects. The genetic correlations among the measures collected at age 12 varied between .63 and 1.00.


CONCLUSIONS
The genetic overlap between questionnaire ratings and the DSM-IV diagnosis of ADHD is high. Clinical and research implications of these findings are presented.
Derks
Eske M
EM
Department of Biological Psychology, Vrije Universiteit, Van der Boechorststraat 1, Amsterdam, 1081 BT, The Netherlands. em.derks@psy.vu.nl
Hudziak
James J
JJ
Dolan
Conor V
CV
van Beijsterveldt
Toos C E M
TC
Verhulst
Frank C
FC
Boomsma
Dorret I
DI
D001288:Attention / Q000502:physiology*; D001289:Attention Deficit Disorder with Hyperactivity / Q000453:epidemiology* / Q000209:etiology / Q000235:genetics*; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000453:epidemiology / Q000209:etiology / Q000235:genetics; D002648:Child; D004777:Environment; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D015999:Multivariate Analysis; D015995:Prevalence; D012727:Sex Characteristics