no I don't partake in mind-altering substances unless you're including alcohol, but I don't take that in mind-altering quantities, infact I don't like to be drunk.
I have dabbled with various drugs in the past and from about 16 to 20 I used to get stoned (dope) almost every day and really enjoyed it. Infact about 20 I realised I had hardly ever had sex without being stoned! It wasn't a big conscious decision to stop, it just wasn't doing much for me anymore. I don't think I have an addictive personality. Now I find that the world around and 'reality' is a fairly mind-altering experience.