Barefoot In The Head, by Brian Aldiss
'Set in a Europe some years after a flare-up in the Middle East led to Europe being attacked with bombs releasing huge quantities of long-lived hallucinogenic drugs. Into an England with a population barely maintaining a grip on reality comes a young Serb, who himself starts coming under the influence of the ambient aerosols & finds himself leading a messianic crusade. The narration & dialog reflects the shattering of language under the influence of the drugs, in mutating phrases & puns & allusions, in a deliberate echo of Finnegans Wake"