Don't worry Tim. Drugs are a personal choice, fuelled by many reasons including environment, experience, mind set, availability and a whole host of other reasons. Whether you condone or not is not going to impact it, and certainly doesn't make me re-assess my opinion of you.
Most people understand that drugs are harmful on some level. Most people understand that there is at least some aspect of a drug that is appealing to that individual. Managing that (or not managing that) is where people tend to differ.
As an aside, most families have a family member who suffers from some mental health issue or another. Usually several. I don't think it is something to feel anything about "admitting" it. They are health issues, not something to be ashamed of or hidden away. Be concerned for someone's privacy, maybe, but never feel it is something that should be hidden for any other reason.
Interestingly enough I just read a paper last week which was all about using psychoactive drugs, specifically magic mushrooms and LSD for treating depression and psychosis! It seems counter intuitive, who knows. Probably more of an issue at triggering a psychotic response is skunk. It's a very high THC version of cannabis and is known to trigger psychosis in people who have a genetic predisposition towards psychosis, such as those who could have latent bipolar or schizophrenia. It is also widely available as most grass on the street is now of a skunk variety.
I think creative types are more likely to be experimental risk takers... that is a different issue to psychological addiction, and completely separate to physical addiction or having a genetic predisposition to any and all of them. Certainly everyone can develop psychological addiction to substances. Indeed OCD is partly the same thing applied to activiies rather than substances.
Additionally,being expermental and being creative are almost the same thing. That only means that a creative is perhaps more likely to TRY drugs. That is most definitely NOT the same as psychological dependence or physical dependence, or the genetic predisposition to either.
All good stuff Tim. It is good that these things get debated. That you are not a drug user, other than alcohol, means that you want to get a handle on it.... which is notoriously difficult in any area, never mind drugs. Try understanding the joy of a motorcycle to someone who has never even been in a car. They understand exhiliration, but their frames of reference would be limited. It is good to grapple with concepts. That aside... of course drugs have benefits and appeal. Otherwise why would anyone take them? To deny that is like denying that riding a motorcycle is fun and focusing only on all the crash injuries and deaths.
To have a realistic view we have to understand appeal, risk and potential damage.