A Scanner Darkly (2006)

Synopsis
The war on drugs has been lost, and when a reluctant undercover cop is ordered to spy on those he is closest to, the toll that the mission takes on his sanity is too great to comprehend in director Richard Linklater's rotoscoped take on Philip K. Dick's classic novel. With stratospheric concern over national security prompting paranoid government officials to begin spying on citizens, trust is a luxury and everyone is a suspected criminal until proven otherwise. Bob Arctor (Keanu Reeves) is a narcotics officer who is issued an order to spy on his friends and report back to headquarters. In addition to being a cop, though, Arctor is also an addict. His drug of choice is a ubiquitous street drug called Substance D, a drug known well for producing split personalities in its users. ~ Jason Buchanan, All Movie Guide