Volume 105, Issue 10 pp. 1844-1853

Peer substance involvement modifies genetic influences on regular substance involvement in young women

Arpana Agrawal

Arpana Agrawal

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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Sumitra Balasubramanian

Sumitra Balasubramanian

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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Emily K. Smith

Emily K. Smith

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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Pamela A. F. Madden

Pamela A. F. Madden

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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Kathleen K. Bucholz

Kathleen K. Bucholz

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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Andrew C. Heath

Andrew C. Heath

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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Michael T. Lynskey

Michael T. Lynskey

Washington University School of Medicine, Department of Psychiatry, St Louis, MO, USA

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First published: 15 September 2010
Citations: 36
Arpana Agrawal, Washington University School of Medicine, Department of Psychiatry, 660 S. Euclid, CB 8134, Saint Louis, MO 63110, USA. E-mail: [email protected]

ABSTRACT

Aims  Peer substance involvement (PSI) is a robust correlate of adolescent substance use. A small number of genetically informative studies suggest that shared genetic and environmental factors contribute to this association. We examine mechanisms by which PSI influences the etiology of regular substance involvement (RSI), particularly in women.

Design  Population-based cohort study of twin women from the US Midwest.

Participants  2176 twin women.

Measurements  To examine the relationship between self-reported PSI during adolescence and a composite RSI representing regular tobacco, alcohol and cannabis use during young adulthood, using genetically informative correlation, moderation and joint correlation-moderation models.

Findings  There was evidence for a significant additive genetic X environment interaction. PSI was moderately heritable (h2 = 0.25). Genetic, shared and non-shared influences on RSI overlapped with influences on PSI (genetic correlation of 0.43). Even after controlling for these shared genetic influences, RSI was more heritable in those reporting greater PSI.

Conclusions  While young women may select peers based on certain dispositional traits (e.g. permissiveness towards substance use), the social milieu constructed by PSI does modify the architecture of increased RSI in those individuals with increasing levels of PSI being associated with stronger expression of heritable influences.

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