Environmental adversity and increasing genetic risk for externalizing disorders.
BACKGROUND
Studies of gene-environment interplay in the development of psychiatric and substance use disorders are rapidly accumulating. However, few attempts have been made to integrate findings and to articulate general mechanisms of gene-environment influence in the emergence of psychopathology.


OBJECTIVE
To identify patterns of gene-environment interplay between externalizing disorders (antisocial behavior and substance use) and several environmental risk factors.


METHODS
We used quantitative genetic models to examine how genetic and environmental risk for externalizing disorders changes as a function of environmental context.


METHODS
Participants were recruited from the community and took part in a daylong assessment at a university laboratory.


METHODS
The sample consisted of 1315 male and female twin pairs participating in the assessment of the Minnesota Twin Family Study at age 17 years.


METHODS
Multiple measures and informants were used to construct a composite of externalizing disorders and composite measures of 6 environmental risk factors, including academic achievement and engagement, antisocial and prosocial peer affiliations, mother-child and father-child relationship problems, and stressful life events.


RESULTS
A significant gene x environment interaction was detected between each environmental risk factor and externalizing such that greater environmental adversity was associated with increased genetic risk for externalizing.


CONCLUSIONS
In the context of environmental adversity, genetic factors become more important in the etiology of externalizing disorders. The consistency of the results further suggests a general mechanism of environmental influence on externalizing disorders regardless of the specific form of the environmental risk.
Hicks
Brian M
BM
Department of Psychology, University of Minnesota, 75 E River Rd, Minneapolis, MN 55455, USA. hicks013@umn.edu
South
Susan C
SC
Dirago
Ana C
AC
Iacono
William G
WG
McGue
Matt
M
D000293:Adolescent; D000437:Alcoholism / Q000235:genetics* / Q000523:psychology; D000987:Antisocial Personality Disorder / Q000235:genetics* / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D004200:Diseases in Twins / Q000235:genetics* / Q000523:psychology; D005260:Female; D006801:Humans; D007389:Internal-External Control; D008016:Life Change Events; D008137:Longitudinal Studies; D008297:Male; D008910:Minnesota; D008957:Models, Genetic; D010379:Peer Group; D010552:Personality Assessment; D012307:Risk Factors; D012931:Social Environment; D012933:Social Identification; D019966:Substance-Related Disorders / Q000235:genetics* / Q000523:psychology; D014429:Twins, Dizygotic / Q000235:genetics / Q000523:psychology; D014430:Twins, Monozygotic / Q000235:genetics / Q000523:psychology