How does Boyle use cinematography to represent the different stages of drug use in the motion picture, Trainspotting?

In Trainspotting, Boyle incorporates complex cinematography to represent the different stages of drug use. The audience is shown powerful hallucinations in which it can be hard to tell fact from fiction. Boyle uses the camera to advantage by showing Renton falling through floors and swimming through a toilet. These scenes help the viewer grasp the fantasy world in which a heroin addict lives after a hit. Additionally, the viewer sees a graphic depiction of the strenuous, painful and frightening drug withdrawal process Renton endures in his parents' house. As Renton hallucinates and is wracked by cravings for drugs, the viewer can experience his pain while also knowing that he will be better off without drugs.