I'm at the point of a chapter in my Dissertation where I am looking at the medical aspects of drugs - in this part, addiction.
There is plenty of evidence to support drug addiction is a medical issue, not only from commentators but also from medical groups (google - 'Pain and Substance Misuse: Improving the patient experience').
Obviously there is a criminal aspect to drug addiction which is through committing crimes to fund their habit. Obviously it differs with drugs (crack cocaine, Opiates etc).
Just wondered what your view on this was. I'll add more when I get the evidence and write a bit more. Just could do with a discussion.