It starts off with peer pressure and this causes people to become addicted to it once they first try it. Once the addiction starts, those that are addicted realize that they need some kind of escape from the stress that haunts them. So this causes them to take the drug again and again. The availability of heroin also contributes to how people become addicted to it. It is so readily available that people can access it so easily. It is really hard to combat the quantity of heroin being distributed.