ABSTRACT
This chapter focuses on how specific natural variations in genes can make individuals more susceptible to the effects of drugs and biological addiction. In reviewing the effects of genes on any behavior, including addiction, the most important concept to understand is that genes do not code for any behavior. In other words, it is a common misconception to think that genes control behavior. Whether or not a person will become an addict—and how fast and strongly—depends on many things, including his or her surroundings and personal history, what types of drugs are involved, and the way that a person’s body and brain respond to drugs. Individuals are impacted by their genetic makeup, having predispositions to react to certain chemicals. However, this is not a one-to-one relationship. Rather, there is a connection between genes and environment. People behave and react based on the interplay between predisposition and experience—which can best be viewed through the notion of nature-via-nurture. Thus, whether someone becomes addicted to drugs or alcohol is partially explained by their genetic predisposition and partly their environmental history.
