There's no one size fits all answer to this, I believe. I think you need to take into account your medications, your past history (any addiction issues, etc.), your current level of stability, and how alcohol affects you.

Like, I don't have addition issues, I'm on a drug that doesn't (or hasn't for me) caused any side effects or complications if I drink, and I'm very safe and functional, and drinking mostly just makes me a little goofy. Therefore I can drink in moderation with no ill effects.

If it were someone with prior addiction issues, on a cocktail with side effects or complications when combined with alcohol who is either very depressed or very manic, or tends to get angry and violent when they drink...you can see why them drinking is not a good idea.