Familial aggregation for conduct disorder symptomatology: the role of genes, marital discord and family adaptability.
BACKGROUND
There is extensive evidence of statistical associations between family discord/ maladaptation and antisocial behaviour in the children, but questions remain on the extent to which the psychopathological risks are genetically or environmentally mediated.


METHODS
Twin pairs (N = 1,350), aged 8 to 16 years, in the general population-based Virginia Twin Study of Adolescent Behavioral Development were assessed using the Child and Adolescent Psychiatric Assessment interview administered separately to both twins and both parents. Structured interviews for parental lifetime psychiatric disorders were also administered to the mothers and fathers. Maternal reports on Olsson's Family Adaptability and Cohesiveness questionnaire and the Dyadic Adjustment Scale were used as indices of the family environment. A path analytical model based on an extended twin-family design was used to test hypotheses about parent offspring similarity for conduct disorder symptomatology.


RESULTS
Family discord and maladaptation, which intercorrelated at 0.63, were associated with a roughly two-fold increase in risk for conduct disorder symptomatology. When parental conduct disorder was included in the model the environmental mediation effect for family maladaptation remained, but that for family discord was lost.


CONCLUSIONS
It is concluded that there is true environmental mediation from family maladaptation, operating as a shared effect, which accounts for 3.5 % of the phenotypic variance. The assumptions underlying this genetic research strategy are made explicit, together with its strengths and limitations.
Meyer
J M
JM
Virginia Institute for Psychiatric and Behavioral Genetics, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0003, USA.
Rutter
M
M
Silberg
J L
JL
Maes
H H
HH
Simonoff
E
E
Shillady
L L
LL
Pickles
A
A
Hewitt
J K
JK
Eaves
L J
LJ
D000223:Adaptation, Psychological; D000293:Adolescent; D000328:Adult; D002648:Child; D019955:Conduct Disorder / Q000235:genetics* / Q000523:psychology*; D005190:Family / Q000523:psychology*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008960:Models, Psychological; D011569:Psychiatric Status Rating Scales; D012931:Social Environment; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D014768:Virginia