It's not a simple decision that people make to use drugs or not use drugs. All the traditional approaches to provide kids with information about the dangers of smoking, drinking, and using illicit drugs have largely failed. The problem is much broader, and you need a holistic approach, one that's designed to target several different risk factors. A lot of the life skills that we're teaching are really protective factors. They're a way of buttressing kids up and decreasing their motivations.
Various factors promote drug use.
For different kids, different factors seem to be more important. Some kids may use drugs if, for example, they feel uncomfortable in social situations. They may use drugs because they think it's going to help them deal with their social anxiety. By teaching them anxiety management techniques you give kids adaptive life skills, and those kids won't need to medicate themselves to deal with negative feelings coming from social anxiety. Another aspect of this is that kids want to use drugs to gain entree into a certain peer group, to be accepted by a certain group of kids, or as a way of being more popular.