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 and a common misconception to think that genes control behavior. Polymorphisms in genes that are found to be more common in the addicted compared to non-addicted group are further investigated as genes that are associated with addiction. Investigations in the genetics of addiction and substance abuse are a gene-environment interaction (GxE) model. Individuals are impacted by their genetic makeup, having predispositions to react to certain chemicals. 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 on their environmental history.
