Being the brother of a wine grower and involved in the wine trade a bit it's a bit difficult to avoid the actual drinking. However, it's good (on the one side) this wine business is a bit on the posh side and so I never get drunk really, bc that's not something you're supposed to do within these circles, right? Well, the posh thing is a bit off-putting bc of the influx of snobs, but then you have people who really like and enjoy good wine. It's a bit like the peeps into music for the sake of music and the hipster clowns who are in it for the sake of "accumulating cultural capital" or some shit.
Is alcoholism a problem within those circles? Difficult to say, the overall amount of what's being drunk is fairly high I'd suppose, but you usually don't get drunk, It's usually one, two glasses an evening or so. I am in my mid 30s now, and the last time I was actually drunk as fuck was my early 20s. On the other hand I know people within the wine business who are definitley alcoholics (got their driver's licence suspended and things like that).
Someone mentioned upthread that some of his heavy drinking mates get paranoid? That's osmething new, none of the drinkers I know actually appear paranoid. Some people I know who'd smoke lots of weed on the other hand are like that. As to the question of quitting - of course it'S all about the circumstances, if a lot of your mates drink and you drink with them, you need new non-boozing friends then.
Gladly I never really smoked, except for the period my gf at the time was a fairly heavysmoker, so I started, too. When we split up, I stopped immediately.
As for the other stuff considered drugs I only smoked weed a bit, but the experience was rather lame so I didn't go any firther.