Scanners was originally released in 1981 and I saw this for the first time on video in about 1986/87. The film was directed by horror meister David Cronenberg (The Fly, Existenz, Naked Lunch, Dead Ringers). Scanners tells the story of a group of people (scanners) who develop various psychic powers after their mothers were given experimental drugs in the 1950's and 60's.
The main character is a homeless drifter tortured by his powers (without drugs the scanners are constantly bombared with other peoples random thoughts) he is taken in by the doctor who did the experiments with the mothers and given a drug "hypnocil" that controls their powers and blocks the "voices". Another scanner (Michael Ironside) trys to lure the main character into using his powers for evil. The film is probably most famous for a scene when the evil scanner makes a another scanners head explode like a gore splattered balloon!