The literature has identified four categories of risk factors for drug use: (1) cultural and societal factors such as laws and social norms favorable to drug use, (2) interpersonal factors such as positive family attitudes toward drug use and family conflict, (3) psychobehavioral factors such as early and persistent problem behavior and academic failure, and (4) biogenetic factors such as an inherited susceptibility to drug abuse and psychophysiological vulnerability to drug effects. No single factor or even a small group of factors is the sole or determining risk or protective condition. In addition, many of these risk and protective influences change as a function of developmental period. Moreover, some factors are important for many groups and others are relevant only for specific populations. Most important, this area of cross- cultural comparative research is not well developed, and current conclusions are only preliminary. However, it is clear that all intervention programs must be multifaceted and specialized to the developmental stage and characteristics of the population. Finally, all prevention efforts must be broad rather than focusing on a single problem behavior. Figures, tables, and 53 references