A number of implications can be drawn from this study. For example, the genetic correlation between PPD and DV indicates that an adolescent’s desire to affiliate with deviant peers is indicative of a potential risk for use and dependence. Furthermore, results of studies such as these can aid in the identification of environments to select participants for molecular studies. For example, the current study showed that genetic variance is greater among individuals with fewer delinquent peers, and those with extremely high levels of PPD. Thus, the phenotypic variance explained by each contributing QTL might increase in populations at either extreme and thus be easier to detect.
