Individual vulnerability to addiction.

The process of addiction is often studied in the neurosciences as a function of the quantity or type of substance consumed, with the ultimate goal of counteracting these effects by other pharmacological means. However, epidemiology and clinical research have extensively demonstrated that most individuals who use drugs do not develop dependence. Numerous factors may explain an individual's propensity to addiction. This review discusses these paradigms and summarizes research on individual differences that encompass cultural and sociodemographic factors, psychiatric or psychological vulnerability, and biological or genetic propensity to addiction. Although these different factors often interact in the expression of vulnerable phenotypes, it is possible to alter or control specific sources of vulnerability. For these reasons, integrating individual vulnerability to addiction across different research disciplines is likely to provide the greatest advances for intervention and prevention efforts.