I've done some research on alcoholism. After one year of sobriety a person has a 50% chance of relapse statistically speaking. That number continues to drop with time and levels off at around 15% after five years. Alcoholism affects roughly 15% of the overall population so after five years you have as much of a chance of relapse as any member of the population has of becoming an alcoholic. I would imagine this framework could be established for other addictions as well.
