Identifying shared environmental contributions to early substance use: the respective roles of peers and parents.
Although behavior genetic studies have suggested that early substance use is primarily environmentally mediated, no study has sought to identify the specific sources of environmental variance. Using data obtained from multiple informants, this study assessed the contributions of peer deviance and parent-child relationship problems to substance use in 14-year-old male and female twins (N = 1,403) drawn from the Minnesota Twin Family Study (MTFS). All three phenotypes were influenced primarily by shared environmental variance (average c(2) =.51), as was the overlap among them. Moreover, peer deviance and parent-child relationship problems accounted for approximately 77% of the variance in early substance use. Findings also indicated that peer deviance, but not parent-child relationship problems, accounted uniquely for variance in early substance use.
Department of Psychology, University of Minnesota, Minneapolis, MN 55455, USA. bwalden@tfs.psych.umn.edu
Brent
B
Walden
Matt
M
McGue
William G
WG
Lacono
S Alexandra
SA
Burt
Irene
I
Elkins
D000293:Adolescent; D000704:Analysis of Variance; D004200:Diseases in Twins / Q000235:genetics; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008910:Minnesota; D015233:Models, Statistical; D010287:Parent-Child Relations; D010379:Peer Group; D010641:Phenotype; D012307:Risk Factors; D012931:Social Environment; D012932:Social Facilitation; D019966:Substance-Related Disorders / Q000235:genetics / Q000523:psychology*