Its self medication. The vast majority of drug users are self medicating for trauma, abuse, mental illness, stress disorders, and undiagnosed medical problems. They see a benefit in it, until it isn't benefitting them and only causing additional medical concerns. If we funneled more money into treatments for mental health and trauma (yah, I know, where to find the money...) as well as policing we could take a huge chunk out of this problem before it even begins.