This is another novel by Irvine Welsh following pretty much the same trajectory as his others. Like "Marabou Stork Nightmares", "Filth", and "Porno", it's a story of a man working towards a breakdown. There are lots of drugs taken; this time it's mostly alcohol, and there's some welcome reflections on the destructive slow descent from social drinker to alcoholic. There's good use of mulitple perspectives to show each of the main character's thought processes, though not for any other real reason. There's some graphically-described sex, and one truly revolting scene (as always). Relationships and the banal malevolence of office politics are acutely described - Welsh has a razor-sharp eye if nothing else.
The conceit of the novel is that, after Dorian Grey, a man suffers the consequences of another's substance abuse. Quite what this is meant to suggest I don't know. Apart from some musing on the symbiotic nature of enemies and nemesis', it's not really an allegory or a metaphor for anything, it's just a conceit to allow some highly vivid descriptions of physical decay.
The thing is, it's not only following a law of diminishing returns (so that these retreads on familiar material get progressively worse, "Porno" excepted because of his all-too-evident fondness of the old characters). To progress with your art you have to struggle. There's no struggle here, no development. It's slightly more "literary" in that there are more allusions and quotations, but far less literary than "Trainspotting" because there's no depth to the novel. It's in present-tense, this-this-this style which allows no reflection and no real substance.
Welsh really must get out of his comfort zone. If he would write about street culture as its happening now, or about the corruptions of power without resorting to bodily metaphors, or about the class war from the post-modern perpective, I'd be interested. But he's not pushing himself, and it's getting boring.