A Longitudinal Study of Common Childhood Psychopathology³

Marjolein J. H. Rietveld¹, Toos van Beijsterveldt¹, Jolande C. van der Valk², F. C. Verhulst², and Dorret I. Boomsma<sup>1

1</sup> Department of Biological Psychology, Vrije Universiteit, Amsterdam, The Netherlands
² Department of Child and Adolescent Psychiatry, Sophia Children's Hospital, Rotterdam, The Netherlands

At three occasions, we collected data on behavior and emotional problems in a large sample of Dutch twins, born between 1986 and 1991. Twins were aged 3, 7 and 10 years. Nearly 3700 parents completed the Child Behavior Checklist (CBCL) on at least one of these occasions. Around 2000 pairs have complete longitudinal data by maternal report. Of these cases, nearly 50% of the fathers completed an additional CBCL. Compared to fathers, mothers report more behavior problems in their children. The discrepancy between parents is observed for each syndrome, for both genders, and at each age. When boys are compared to girls, we find most significant differences for syndromes that are related to externalizing problem behavior. At age 3, boys already display more overactive, aggressive, and oppositional behavior. Twin correlations calculated for each trait at each age are suggestive of an ADE model for overactive/attention problems and an ACE model for the other syndromes. Concerning stability in problem behavior, phenotypic correlations are moderate for the interval from age 3 to age 7 (between .20 and .50), and large for the interval from age 7 to age 10 (between .40 and .75). Externalizing problem behaviors display more stability compared to internalizing problem behaviors. The observed stability in problem behavior appears to be due to genetic influences. We intend to explore the data by using a multi-informant longitudinal design to address the genetic and environmental contributions to stability and change in common psychopathology across childhood age.