[dgacmu]

You might be surprised. I have some friends who did a lot of drugs at one point or another in their life and ended up later holding a clearance. Addiction might be different, but I wouldn't let your past deter you from looking if there was an opportunity you really liked. The clearance process looks more at if you have a problem that can be exploited.

(Now, that said, holding a clearance can be a pain for other reasons already detailed in this thread. A lifetime ban on talking about some things can be an annoying cognitive burden to carry, also.)