Well, what was in the coffee, TEd? But, actually, Kesey was quoted as saying that once he embarked on his romance with LSD that the art of novel writing didn't seem as important anymore. Huh?
Usually artists have a pretty driven impulse to create, and use drugs, alcohol (or the problems and pain associated therewith) as a catalyst to their creativity. So he wrote "One Flew Over the Cuckoo's" nest when he was 23, followed that with "Sometimes A Great Notion" a couple of years later (his only critically acclaimed works), and then didn't publish another major novel until '92 which was mediocrely received. It seems that in this case the drugs really became the man, shall we say, and his writing life became an asterisk. Which means he probably had a few more great books in him that never came out...which is really a shame. But, on the other hand, his drug usage didn't seem to wreak havoc in his life (unless you want to equate the loss of a great artist's creatic impulse in that category), and he enjoyed himself, raised a loving family, and had a good life...so, who's to say?