Only for one period of his life, and the stuff he’s written after he got clean is some of the best stuff he’s ever written…
King may have been on tons of coke (and drinking bottles of Scope mouth wash) while writing some books, it was in spite of it, not because. Those books don’t necessarily reflect the characteristics of cocaine.
It’s not like what speed is to On The Road, as that book actually reads like someone tweaking out.