[YorkshireSeason]

As of July 2019, there is no know way that cures drug addition with even moderate degrees of success. Indeed, even the very definition of addiction is still controversial. From [1]: "[D]efining addiction is not an easy task and still represents a considerable source of scholarly dispute. The term addiction has been and it is still used in at least three different ways. [(i) I]t is used as a lay term, which entered the English language in the late sixteenth century (maybe owing to Shakespeare) to indicate inclination or proclivity for certain habits or activities, in both its positive and negative connotations, including excessive drinking and smoking. [(ii)]Since the late nineteenth century, addiction is also used as a medical term to indicate pathological, compulsive drug use [...] [(iii) A]ddiction is used as a psychological construct to indicate a compulsive motivational drive [...] Instances of all three meanings abound in the scholarly literature, sometimes within the same paper."

OTOH, drug dealers, too, obtain economies of scale by concentrating drug users in close physical proximity (and vice versa). It seems to be plausible to assume that the easy availability of drugs is itself causally contributing to drug use and drug addiction.

[1] A. Badiani, Is a 'general' theory of addiction possible? A commentary on: a multistep general theory of transition to addiction. https://www.ncbi.nlm.nih.gov/pubmed/24888430