5. A Scanner Darkly
Warner Independent Pictures
The Drug: Substance D While it might be cheating a little to include a film about a fictional drug (although the fictional adrenochrome in Fear and Loathing in Las Vegas set a precedent), Philip K. Dick's A Scanner Darkly - adapted to the screen by Richard Linklater - is a worthy addition, given that it explores the paranoid side of drug addiction better than most of its rivals. Set in a future where the government have long since lost the war on drugs, A Scanner Darkly stars Keanu Reeves as detective Bob Arctor, assigned to the underworld in order to track down the distributors of Substance D, which he himself becomes addicted to. Linklater shot the film digitally then animated the footage using the interpolating rotoscope technique previously employed on the ambitious but flawed Waking Life - the result is a perfect expression of the frail, paranoid characters who inhabit this future realm, where undercover agents wear shimmer suits to mask their identity and the thread which ties the characters to reality wears increasingly thin. It's also easily the most faithful Philip K. Dick adaptation to date.