title: A common genetic factor explains the covariation among ADHD ODD and CD symptoms in 9-10 year old boys and girls.
abstract: Previous studies examining the covariation among Attention Deficit Hyperactivity Disorder (ADHD), Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD) have yielded inconsistent results. Some studies have concluded that the covariation among these symptoms is due to common genetic influences, whereas others have found a common environmental overlap. The present study investigated the genetic and environmental correlations among these three childhood disorders, based on a sample of 1,219 twins, age 9-10 years. A latent externalizing behavior factor was found to explain the covariance among ADHD, ODD and CD symptoms. Genetic influences explained more than half of the variance in this externalizing factor in both boys and girls. There were also unique genetic and environmental influences in each set of symptoms, suggesting some etiological independence of the three disorders. Our findings have implications for molecular genetic studies trying to identify susceptibility genes for these disorders.
authors.affiliation: Department of Psychology, University of Southern California, 3620 S. McClintock Ave., Los Angeles, CA 90089-1061, USA. Tuvblad@USC.EDU
authors.forename: Catherine
authors.initials: C
authors.lastname: Tuvblad
authors.forename: Mo
authors.initials: M
authors.lastname: Zheng
authors.forename: Adrian
authors.initials: A
authors.lastname: Raine
authors.forename: Laura A
authors.initials: LA
authors.lastname: Baker
mesh_terms: D001289:Attention Deficit Disorder with Hyperactivity / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D019958:Attention Deficit and Disruptive Behavior Disorders / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D002648:Child; D019955:Conduct Disorder / Q000175:diagnosis / Q000235:genetics* / Q000523:psychology; D004247:DNA / Q000032:analysis / Q000235:genetics; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D018895:Microsatellite Repeats; D012931:Social Environment; D011795:Surveys and Questionnaires; D014427:Twins / Q000235:genetics*
chemical_list: D004247:DNA