A Twin Study of ADHD Symptoms in Early Adolescence: Hyperactivity-impulsivity and Inattentiveness Show Substantial Genetic Overlap but Also Genetic Specificity

TY - JOUR

T1 - A Twin Study of ADHD Symptoms in Early Adolescence: Hyperactivity-impulsivity and Inattentiveness Show Substantial Genetic Overlap but Also Genetic Specificity

AU - Greven, Corina U.

AU - Rijsdijk, Fruehling V.

AU - Plomin, Robert

PY - 2011/2

Y1 - 2011/2

N2 - A previous paper in this journal revealed substantial genetic overlap between the ADHD dimensions of hyperactivity-impulsivity and inattentiveness in a sample of 8-year old twins drawn from a UK-representative population sample. Four years later, when the twins were 12 years old, more than 5,500 pairs drawn from the same sample were rated again on the DSM-IV based Revised Conners' Parent Rating Scale to assess symptoms on both ADHD dimensions. Heritabilities were high (around 70%) for both hyperactivity-impulsivity and inattentiveness and evidence for etiological sex differences was absent. The critical finding was a genetic correlation of 0.55, indicating that hyperactivity-impulsivity and inattentiveness are substantially influenced by the same genes but that the two dimensions also show large and significant unique genetic effects. These results in early adolescence confirm our findings in middle childhood, providing evidence for substantial genetic overlap as well as genetic heterogeneity of the ADHD dimensions. Future genetic studies should investigate the ADHD dimensions separately.

AB - A previous paper in this journal revealed substantial genetic overlap between the ADHD dimensions of hyperactivity-impulsivity and inattentiveness in a sample of 8-year old twins drawn from a UK-representative population sample. Four years later, when the twins were 12 years old, more than 5,500 pairs drawn from the same sample were rated again on the DSM-IV based Revised Conners' Parent Rating Scale to assess symptoms on both ADHD dimensions. Heritabilities were high (around 70%) for both hyperactivity-impulsivity and inattentiveness and evidence for etiological sex differences was absent. The critical finding was a genetic correlation of 0.55, indicating that hyperactivity-impulsivity and inattentiveness are substantially influenced by the same genes but that the two dimensions also show large and significant unique genetic effects. These results in early adolescence confirm our findings in middle childhood, providing evidence for substantial genetic overlap as well as genetic heterogeneity of the ADHD dimensions. Future genetic studies should investigate the ADHD dimensions separately.

KW - ADHD

KW - Inattentiveness

KW - Hyperactivity-impulsivity

KW - Etiology

KW - Twin study

U2 - 10.1007/s10802-010-9451-9

DO - 10.1007/s10802-010-9451-9

M3 - Article

SN - 1573-2835

VL - 39

SP - 265

EP - 275

JO - Journal of Abnormal Child Psychology

JF - Journal of Abnormal Child Psychology

IS - 2

ER -