Adolescent behaviors, like virtually all other behavioral outcomes that have been investigated to date, show evidence of considerable genetic influence. However, genetic influences on adolescent behavior appear to be particularly dynamic, perhaps reflecting the nature of this developmental period. Parallel to the dramatic shifts in risk-taking behavior that occur across adolescence, genetic influences also increase in importance across adolescence for key behaviors, such as alcohol use and problems. Increases in genetic influence likely reflect, in part, the increasing ability of adolescents to select and shape their environments. The ability of adolescents to express their predispositions for outcomes such as substance use also varies dramatically as a function of their environments, with aspects of the home environment, peer network, and community playing a role in the extent to which genetic predispositions are engendered or diminished. Further, there are multiple pathways of genetic risk, and these too show developmental changes across adolescence. Indeed, the period of adolescence appears to be ripe with dynamic genetic effects.
