I've never dealt with drug addiction myself, but I've had close friends who I've witnessed go through it & most people could say the same. Johann Hari makes the point from his research that drug addiction (& the struggles that go along with it) can be more of an "adaptation of environment", rather than a strictly chemical dependence. Alot of what he also goes into is how policies around the world in how addiction is treated and percieved is wrong , as well as radically diff ways some countries have changed this (& had success). Its a good interview that comes along with some pretty eye-opening findings.
For the fuller interview:
http://www.democracynow.org/2015/2/4/johann_hari_everything_we_know_about