I would say that if my drinking (drug use, whatever) in some way diminishes my relationship with God, then it's a problem. Other people's eyes have very little to do with it IMO.
Drinking some is OK, but getting blind drunk (to the point that your relationship with God suffers or to the point that you hurt others) is wrong. There is a line there, we all have to find it for ourselves.
If you're looking for the scripture... God's word from Isaiah 29:9 "Be stunned and amazed, blind yourselves and be sightless; be drunk, but not from wine, stagger, but not from beer." (note: I do not post this with intent to support any argument)
What if taking psychotropic drugs increases my relationship with God? Is that a personal problem, or a problem with reality?
Neither. There are several religions that use psychotropics as sacraments. Rastafarians use cannabis, American Indians use Peyote, and there is a Brazilian church that uses a tea with a substance called DMT in it. As far as I am concerned, whatever method you use to strengthen your relationship with God is the right one.
Jesus healed with weed because his employer didn't make him pee into a sample cup every so often......
i'm not giving you my own opinion. i was giving you what the Bible says about not being a stumbling-block to other people. all things are permissive, but not all things are healthy. i'm called to glorify God. if my drinking diminishes my ability to relate God to others...to glorify Him...because of some pre-conception in their mind about people who drink..or because they'd instantly label me a hypocrit...then i won't do it in their presence. less of me and more of Him is the idea. i'm not very legalistic about drinking. i drink. i just don't like to see bible verses used to support something so outside of the context their written within.