Irwin D. Waldman1, David A. Hay2, & Florence Levy3
It has long been recognized that there is meaningful heterogeneity in childhood and adolescent antisocial behavior (ASB). Recently, developmental psychopathology researchers have focused on age-of-onset as an important source of the heterogeneity in ASB. Children with early-onset ASB appear to have a more stable and pervasive condition with a worse prognosis than children with late-onset ASB. In addition, it has been posited that early-onset ASB is more biologically-based than late-onset ASB, which is posited to be influenced more by environmental risk factors. In this paper, we examine genetic and environmental influences on four clusters of antisocial behaviors – oppositionality, aggression, property violations, and status violations – in a sample of 1534 twin pairs (790 MZ and 744 DZ) and 298 sibling pairs, ages 4-19. These four clusters were shown to differ in median age-of-onset and were isolated using multi-dimensional scaling in a meta-analysis of factor analytic studies of Oppositional Defiant Disorder (ODD) and Conduct Disorder (CD) symptoms. In univariate behavior genetic analyses, a model containing additive genetic and shared and non-shared environmental influences fit best for all four ASB symptom clusters. Heritability was highest for oppositionality and decreased monotonically for aggression, property violations, and status violations. In contrast, shared environmental influences were lowest for oppositionality and increased monotonically for aggression, property violations, and status violations. Multivariate behavior genetic analyses suggested that the monotonically decreasing heritabilities were due predominantly to a common genetic factor, whereas the monotonically increasing shared environmental influences were due predominantly to a common shared environment factor. The implications of these results for a developmentally-informed taxonomy of antisocial behavior are discussed.
Address: mailing address - Department of Psychology, 532 N. Kilgo Circle, Emory University, Atlanta, GA 30322, phone - (404) 727-7430, fax - (404) 727-0372, e-mail - waldman@fs1.psy.emory.edu
1Department of Psychology, Emory University, Atlanta, GA 30322. 2Department of Psychology, Curtin University, Perth, Western Australia, Australia. 3Department of Child and Adolescent Psychiatry, The Prince of Wales Children's Hospital, High Street, Randwick, NSW 2031, Australia.