I know a lot of songwriters like to get pretty tipsy and then write something.
Writing a song (or a classical piece) is very different than sitting at the piano and playing it!
When composing a new piece of music, what you need is a free flow of ideas. If new original music is what your looking for, being concentrated and focused may actually be a bad thing. That is exactly why most composers seldom get the ideas for their music when they sit next to the piano...
Unlike the composer, a performer
must be concentrated and focused when playing a piece.
So I find it hard to believe that wine or drugs or whatever can enhance the quality of a pianist. Actually, I would venture to say, that those who play well while being "high", are playing well
in spite of what they have in their bloodstream, rather than because of it.