A clear mind is the most creative, alot can be made of certain people that used drugs and wrote many great songs, but alot of them are in the grave now and not really doing much good writing anymore too, and since brains are one to a customer, it's kind of hard to do much comparison of what the altered brain creates vs. the unaltered. Having done over 10 years of field research on the effects of drugs and alcohol on the brain, ( code for partying, ;) ), the conclusion I came to was, I wish I had my time and money back, the only thing I created was alot of trouble for myself.........