See, I've always wanted to get a snootful of wine, or smoke a doob, and then try to write. My biggest problem in writing is not skill, it's confidence and my own brain inhibiting me. Maybe a snootful of booze might knock that down and let me just write.
Unfortunately it would never work. My first reaction to being high, regardless of source, is to fall asleep.
Have you considered meditation? It might prove to be a useful tool to 'quiet' that internal critique