title: High activity of monoamine oxidase A is associated with externalizing behaviour in maltreated and nonmaltreated adoptees.
abstract: Individual differences in a functional polymorphism of the promoter of the Monoamine oxidase A (MAO-A) gene might partly explain the increased vulnerability of maltreated children for externalizing behaviour. A sample of 239 internationally adopted boys was studied. Adoptive parents provided the information about abuse and neglect before the adoption and rated externalizing behaviour of their adopted children, using the Child Behaviour Checklist. MAO-A alleles were classified in high and low activity. We found that individuals with high MAO-A activity had more externalizing behaviour than those with low MAO-A activity. No modifying effect of MAO-A on the relationship between early maltreatment on externalizing behaviour was observed. Our results suggest that in severely maltreated children, high MAO-A activity may not protect against the effects of maltreatment but may convey an increased risk for externalizing behaviour.
authors.affiliation: Department of Child and Adolescent Psychiatry, Sophia Children's Hospital, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Esther J M
authors.initials: EJ
authors.lastname: van der Vegt
authors.forename: Ben A
authors.initials: BA
authors.lastname: Oostra
authors.forename: Alejandro
authors.initials: A
authors.lastname: Arias-Vásquez
authors.forename: Jan
authors.initials: J
authors.lastname: van der Ende
authors.forename: Frank C
authors.initials: FC
authors.lastname: Verhulst
authors.forename: Henning
authors.initials: H
authors.lastname: Tiemeier
mesh_terms: D000293:Adolescent; D000300:Adoption / Q000523:psychology*; D002648:Child; D002649:Child Abuse / Q000523:psychology*; D002653:Child Behavior Disorders / Q000201:enzymology* / Q000523:psychology*; D006801:Humans; D008297:Male; D008995:Monoamine Oxidase / Q000378:metabolism*
chemical_list: D008995:Monoamine Oxidase