links in long chains that were relatively easy to break up. Apply this to the drug world, and it may be that an effective intervention would be to focus on the nonprofessional dealers who informally pass drugs on to friends. These people are the equivalent of the high school students with few partners: they might be relatively easy to influence, and breaking just one link in a friendship “chain”—that is, preventing one person from passing drugs on to others—would mean that a large group of people is severed from the distribution network.
