We, of course, do not know and most likely will never know the statistics of successful treatment of patients addicted to gambling. But I not only admit that many are cured, but I have also observed it many times. But this is a question of whether there are former drug addicts or not. After all, it is enough for some kind of stress to occur in a person’s life and the person will fall ill with his disease again. I would call successful cases of healing “controlled addiction.” I first saw this term in an interview with Ingvar Kamprad, the founder of IKEA. He said he had “controlled alcoholism.”
Actually, because of how prevalent and harmful those kinds of addictions can be in any society, I am sure you could get some stadistics or information on how much of a percentage of rehabilitated people get out clinics, you could get a glance of it searching on Google Scholar, for example, for both substances and behavioral dependences.
Out of curiosity, I have read people on the internet who are alledgely former users of hard drugs like crack and they say to have been clean for years, though, I do not doubt there are occasions when the craving could be felt.
I personally know someone who used to smoke much, however, managed to stay off tobacco for many years, he has confessed to me that there have been afternoon when he feels like smoking again, even after more than a decade.
It truly says something about of a former addicted person to opioids or crack could be feeling after some years...