well, you know I'm going to disagree with you Sue
It's a universally acknowledged truth that any man 'high' on something is going to produce controversial work - but not always work worthy of the name art. Pollock was an alcoholic who, had he not died on the road, would have drunk himself into the grave very soon anyway - and probably of all people he was the most surprised that his work was actually called art.
If you need a computer to work out whether something is art, then we've lost the plot. There was a retrospective in London about 7 or 8 years ago, and I did go (only cos one of my sons asked me to join him) - but I do think some of his work would make good wallpaper patterns.
But I'd agree that you can be high and do good things- look at Coleridge and Rossetti
Ms. Emmin very tragically experienced a traumatised childhood - and to her credit has risen above those problems and is capable of some very good art - something akin to German expressionism was an early area in which she was very good - again perhaps an outlet for the troubles of her early years.
But unmade beds - defintitely not............ but you can come and see my unmade bed any Sunday morning for free
Escher was a genius - not just because of his designs but doubly so because of the method he chose to create them - perhaps on a par with Durer even