I highly recommend that you stick with the truth, I believe you are a hero and you have fought all odds to come out of the past. If I were to interview you I would have been really happy with only one question for which you should try to see how you can articulate it.
Recruiters and managers are not really bothered about the past what would really want to know is will you go back to where you came from? They need to understand if they can trust you.
Now with all this in mind frame the response, you should start with what went wrong, what happened, your inner realisation and then your fight against the addiction and then close it by mentioning why you will not go back to your past addiction.
I am sure you will do great things in life, do not hide anything from the hiring team, money, role, promotions will catch up in the long run.