Introduction
Rationale for the Project
Elevated rates of childhood trauma, particularly childhood sexual abuse (CSA)
or physical abuse (PA) have been reported in studies assessing adults and
adolescents presenting for the treatment of alcoholism or drug dependence.
Trauma survivors in treatment have increased rates of alcohol and drug
dependence and other negative outcomes. However, despite highly replicable
relationships between trauma and adverse outcomes, establishing the causal
role of trauma has proved difficult. General population studies have
attempted to control for possible confounding by family background factors (eg., parental alcoholism), that are associated with risks
for both the trauma and its sequelae, by identifying a number of these factors
and then entering them into regression models. Recent investigation in twins,
which have used non-abused co-twins to control for family background, have
confirmed associations with negative outcomes and suggested that prior
statistical controls were overly conservative. The current proposal seeks to
extend these recent methodological advances by better assessing childhood
abuse history in a sub-set of previously interviewed adult twin pairs from
the "Twin89" cohort. This sub-set will consist of a childhood abuse
group [N=500 pairs of 'cases'] in which at least one twin reported CSA
and/or PA in the Twin89 Interview and a matched control group [N-500 pairs]
in which neither twin reported abuse and by obtaining comprehensive
assessments of parents and other siblings. We anticipate that this project
will demonstrate (1) important direct effects of CSA/PA
and indirect effects occurring via family background risk factors that are
associated with risk of abuse on the risk of alcohol dependence and other
psychopathology; and (2) that both direct and indirect effects are more
pronounced in, but not limited to, genetically vulnerable individuals.
Scientific Aims of the Project
The aims can be summarised as follows:
(A) To examine parental predictors of offspring CSA
and PA and to elucidate the routes by which these associations are mediated.
(B) To use data from non-abused co-twins and other siblings to control for
family background risk factors to permit: (1) improved estimation of the
risks for negative outcomes associated with CSA,PA
and (2) examination of routes by which these risks are mediated and
moderated.
(C) To more comprehensively determine the contributions of CSA
and PA, personality disorders, major depression, and anxiety disorders, to
the inheritance of alcohol dependence risk and to identify critical
intervening variables.
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