a1 Pennsylvania State University
a2 Yale University Child Study Center
This study examined genetic and environmental influences on associations among marital conflict about the child, parental monitoring, sibling relationship negativity, and peer delinquency during adolescence and initiation of illegal drug use by young adulthood. The sample comprised data collected longitudinally from same-sex sibling pairs and parents when the siblings were 10–18 years old (M = 14.5 and 12.9 years for Child 1 and Child 2, respectively) and 20–35 years old (M = 26.8 and 25.5 years for Child 1 and Child 2, respectively). Findings indicate four factors that explain the initiation of illegal drug use: two shaped by genetic influences and two shaped by environments shared by siblings. The two genetically shaped factors probably have distinct mechanisms: one a child-initiated coercive process in the family and the other parent and peer processes shaped by the child's disclosure. The environmentally influenced factors seem distinctively shaped by poor parental monitoring of both sibs and the effects of siblings on each other's deviancy.
c1 Address correspondence and reprint requests to: Jenae M. Neiderhiser, Department of Psychology, Pennsylvania State University, 140 Moore Building, University Park, PA 16802; E-mail: email@example.com.
The Nonshared Environment in Adolescent Development project was supported by National Institute of Mental Health Grant R01MH43373 (Time 1, David Reiss, Principal Investigator [PI]) and Grant R01MH59014 (Time 3, Jenae M. Neiderhiser, PI) and by the William T. Grant Foundation (Time 1, David Reiss, PI).