A statistical mediation model was developed within a twin design to investigate the etiology of alcohol use disorder (AUD). Unlike conventional statistical mediation models, this biometric mediation model can detect unobserved confounding. Using a sample of 1410 pairs of Norwegian twins, we investigated specific hypotheses that DSM-IV personality-disorder (PD) traits mediate effects of childhood stressful life events (SLEs) on AUD, and that adulthood SLEs mediate effects of PDs on AUD. Models including borderline PD traits indicated unobserved confounding in phenotypic path coefficients, whereas models including antisocial and impulsive traits did not. More than half of the observed effects of childhood SLEs on adulthood AUD were mediated by adulthood antisocial and impulsive traits. Effects of PD traits on AUD 5‒10 years later were direct rather than mediated by adulthood SLEs. The results and the general approach contribute to triangulation of developmental origins for complex behavioral disorders.
Bibliographical noteFunding Information:
Acknowledgements We acknowledge funding from the US
We acknowledge funding from the US National Institutes of Health and National Institute on Drug Abuse (1R01DA037558-01A1), the Research Council of Norway (226985 and 240061), the Norwegian Foundation for Health and Rehabilitation, the Norwegian Council for Mental Health, and the European Commission under the program ?Quality of Life and Management of the Living Resources? of the Fifth Framework Program (QLG2-CT-2002-01254). TR had full access to all the data in this study and takes responsibility for the integrity of the data and the accuracy of the data analysis. The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
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- Antisocial personality disorder
- Borderline personality disorder
- Statistical mediation model
- Stressful life events
- Substance use
- Twin study