The invention-rich novels of sci-fi fantasist Philip K Dick have long provided Hollywood with a sweetie jar from which it can greedily pluck the tastiest treats.

So we've had the likes of Ridley Scott, Paul Verhoeven and Steven Spielberg cherrypicking the choicest ideas for the likes of Blade Runner, Total Recall and Minority Report.

Director Richard Linklater has determinedly stuck to K Dick's 1977 semi-autobiographical novel of Orwellian state control and drug-induced paranoia.

The story follows the descent into madness of Fred (Keanu Reeves), a Californian undercover narcotics cop who's not unfamiliar with the delights of the chemistry set.

He lives at arms-length with his coke dealer girlfriend (Ryder), vacant acid casualty Woody Harrelson and Robert Downey Jr's motor-mouthed conspiracy theorist.

Thanks to the identity-contorting "scramble suit" he wears as part of his undercover disguise, he's able to carry out the latest orders from his agency.

They tell him to put his buddies under surveillance and then circumstances take an even more absurd twist when he's instructed to spy on himself.

Linklater most notably utilises the "interpolated rotoscoping" technique pioneered in Waking Life to render the characters in a sort of emulsified wash.

The effect is pertinently disorientating and lends proceedings a sort of stoner otherworldliness totally in keeping with K Dick's vision of an America raddled by stimulants.

However, it's all a bit like staying sober in a pub-full of drunks - everyone else is having out-of-body experiences or watching in horror as a pal turns into a cockroach.

There's also the problem that anyone who regularly fries their brains on super-strength, laboratory-designed tabs is likely to suffer severe mind-warping - the I-may-be-paranoid-but-it-doesn't-mean-they're-not-out-to-get-me syndrome.

Ultimately, it doesn't engage - at worst it's dull and, at best, it's a bit too clever for it's own good conspiracy yarn.

Mind you, the bright spark who roped in Harrelson and Downing Jr as a couple of unreconstructed dopeheads deserves an Oscar for inspired casting.

Tim Evans