Kristen C. Jacobson1, & David C. Rowe2
The present study examined genetic and environmental influences on the relationship between attachment to family, attachment to school, and adolescent depressed mood. Data are from the National Longitudinal Study of Adolescent Health (Add Health), a large, nationally representative study of adolescent health and health related behaviors. The Add Health dataset includes a subsample of sibling pairs (e.g., MZ twins, DZ twins, full siblings, half siblings, and unrelated siblings). The statistical package Mx was used to estimate the genetic and environmental influences on attachment to family, attachment to school, adolescent depressed mood and the correlations between these variables. Furthermore, sex differences were also examined. Results from the best fitting model revealed some sex differences. Specifically, genetic factors accounted for approximately one-half the variation in attachment to family and attachment to school among females, but explained only one-third of the variance for males. In contrast, genetic factors were somewhat larger for adolescent depressed mood for males than for females, although non-shared environment explained the majority of variation in depressed mood for both sexes. Significant shared environmental influences were found for boys' reports of attachment to family and attachment to school, but not for females. For both males and females, genetic factors explained approximately one-half of the covariation between attachment to family and attachment to school, with non-shared environmental factors explaining the remainder. Likewise, genetic factors and non-shared environment contributed equally to the covariation of attachment to family and attachment to school with depressed mood for females. However, the covariation between these variables for males could be explained entirely by common non-shared environmental factors.
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1Department of Human Development & Family Studies, The Pennsylvania State University, University Park, PA 16802 2Department of Family Studies, The University of Arizona, Tucson, AZ 85721