Gone, suicide, handgun.
"Because of his intellectual audacity, the chillingly distanced mannerism of his narrative art, the austerity of the pleasures he affords, and the fine cruelty of his wit, [Disch] has been perhaps the most respected, least trusted, most envied and least read of all modern first-rank sf writers." -- 1993 Encyclopedia of Science Fiction
NYT
Wikipedia
His blog. The despair is all there, and so obvious now, hindsight being what it is.