Within a developmental framework, how do shared environmental experiences in the home and community compare to genetic factors in the timing of their influence on the use of psychoactive substances? In considering this question, it is critical to move away from the common static concepts of genetic and environmental influences on human behavior. Genes are temporally dynamic, responding both to internal developmental processes (for example, puberty) and to challenges external to the organism. One such prominent challenge is alterations in the social environment that are often particularly dramatic during adolescence.
