Disputes between rival dealers, between dealers and buyers, and even between rival gangs, can set the stage for fighting and violence. Students involved in drug-related activities may be more likely to carry weapons. Even if a conflict arises that has nothing to do with drugs, the presence of weapons raises the stakes. Clearly the issue of violence in the schools is a complex issue. Conflict relates to drugs.
Drugs relate to gangs.
Gangs relate to violence, and so on. Efforts to prevent drug abuse can have an impact on decreasing conflict and violence as well.