The aim is to develop models that will help organizations plan effective programs to prevent alcohol and drug misuse by young people. By understanding the social processes involved in alcohol and drug use by young people, it should be possible to identify and affect the most important risk factors and protective factors, on an individual and group level, behind substance use. Most of the programs that exist can be classified as primary prevention programs based in the classroom. To increase their chances of success it is often recommended that such prevention programs be supported by other interventions in the local community. These would be initiatives to limit substance availability (supply and education) and to influence the developmental processes of adolescents. The preventive programs differ according to the age of the target group. With younger people the programs are often aimed at postponing regular or normative alcohol use. For the older adolescents the goal is often to avoid binge drinking and the use of illegal substances. These could be regarded as ultimate goals in a goals-means chain. Preventive goals can be formulated in terms of expectations, subjective norms, capacity for coping in specific situations, stable and realistic identities, self-esteem, and perceived control of substance use. Fact-oriented, information-based preventive programs have very little influence on substance use when the program is compared with a control group. Programs aimed at influencing attitudes toward substances also seem to be ineffective. Programs based on an interactive pedagogical perspective seem to be much more effective in changing adolescent substance use. Interactive programs often include components that are aimed at influencing social-psychological factors such as social skills, communication skills, self-esteem, decisionmaking competencies, and group dynamics. Through the use of role playing and an analysis of group behavior, the programs try to make previous subconscious decisionmaking processes conscious. 1 table, 125 references