Maltreatment places children at risk for psychiatric morbidity,
especially conduct problems. However, not all maltreated children develop
conduct problems. We tested whether the effect of physical maltreatment on
risk for conduct problems was strongest among those who were at high
genetic risk for these problems using data from the E-risk Study, a
representative cohort of 1,116 5-year-old British twin pairs and their
families. Children's conduct problems were ascertained via parent and
teacher interviews. Physical maltreatment was ascertained via parent
report. Children's genetic risk for conduct problems was estimated as
a function of their co-twin's conduct disorder status and the
pair's zygosity. The effect of maltreatment on risk for conduct
problems was strongest among those at high genetic risk. The experience of
maltreatment was associated with an increase of 2% in the probability of a
conduct disorder diagnosis among children at low genetic risk for conduct
disorder but an increase of 24% among children at high genetic risk.
Prediction of behavioral pathology can attain greater accuracy if both
pathogenic environments and genetic risk are ascertained. Certain
genotypes may promote resistance to trauma. Physically maltreated children
whose first-degree relatives engage in antisocial behavior warrant
priority for therapeutic intervention.We
are grateful to the Study mothers and fathers, the twins, and the
twins' teachers for their participation. Our thanks to Robert Plomin
for his contributions; to Thomas Achenbach for generous permission to
adapt the CBCL; to Tom Price for comments on earlier drafts of this
manuscript; to Hallmark Cards for their support; and to members of the
E-Risk team for their dedication, hard work, and insights. The E-Risk
Study is funded by Medical Research Council Grant G9806489. Terrie Moffitt
is a Royal Society–Wolfson Research Merit Award holder.