A Scanner Darkly

Set in a not-too-distant future where America has lost its "war" on drugs, Fred, an undercover cop, is one of many people hooked on the popular drug, Substance D, which causes its users to develop split personalities. Fred is obsessed with taking down Bob, a notorious drug dealer, but due to his Substance D addiction, he does not know that he is also Bob. Based on a classic novel by Philip K. Dick. (official distributor synopsis)