I remember years back in an interview Jack White suggested that he didn't smoke pot and that he thought that 'it's cheating' when you write or work creatively while using cannabis. I think Jack is somewhat brilliant, if not a little self important, but it occurred to me that he was wrong; The cannabis is not making the music, it's helping YOU make the music.
Even if it causes you to do so (i.e. you have no motivation or inspiration, but as soon as you smoke you have a surge of creativity), it's still YOU doing it.
Like a skier; he doesn't start his run in a football field, right? No, he starts on a mountain. The mountain helps him ski. The mountain causes him to ski. But HE skis.
At least, that's what I think...