While Cronenberg always had a focused, high-brow thought process behind his films mixed with a delight in exploitation trappings, he was never really much for getting the best performances out of his cast. Sometimes it seems he gets lucky (James Woods and Patrick Magoohan are two examples of actors who need no hand-holding), but other times not so much.
While Cronenberg himself may not sport the greatest acting, he always makes up for it in other ways and in SCANNERS, he never makes the cardinal sin of bookending the drama with action. SCANNERS has a very organic rhythm, plot/character development, action, plot/character development, action, plot/character development, action; like a beating pulse. Screenwriter B.J. Nelson (of LONE WOLF MCQUIAD  fame) would have done better to emulate this in addition to the psychic concept.
While this movie definitely had its high points and it's low points, apparently it was such a huge hit in Sweden, that the distributors contacted Pierre David and demanded another sequel, this time would they get a blockbuster or a franchise killer? SCANNERS III... NEXT!