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Heads do not explode, “Scanners”-style, in David Cronenberg’s new film, but the workings of the mind are very much its subject. On the surface a film about psychological pioneers—and rivals—Sigmund Freud and Carl Jung might seem an uncharacteristic project for the director, but the scenario Christopher Hampton has fashioned from his own play actually fits perfectly with Cronenberg’s career-long obsession with the disjunction between man’s exterior and interior lives, which he’s explored both in his overtly “horror” films and in the ones that are less clearly genre-based. And since he’s demonstrably one of the true intellectuals—and artists—working behind the camera today, it should come as no surprise that “A Dangerous Method” is one of the year’s best films.

The film begins with Jung (Michael Fassbender), an admirer of Freud, adopting the older man’s psychoanalytic method to treat patient Sabina Spielrein (Keira Knightley), a hysterical woman newly arrived at the Swiss hospital where’s he’s on staff. A couple of years later, Jung travels to Vienna to meet Freud (Viggo Mortensen), and the two become friends as well as professional colleagues—so much so that the older man asks Jung to take on the therapy of Otto Gross (Vincent Cassel), a brilliant but unstable associate who’s addicted to both drugs and a lack of restraint. Gross encourages Jung to follow his example and give in to his desires, which leads to an unacceptable patient-doctor relationship with Sabina in spite of Jung’s concern for his wife Emma (Sarah Gadon) and their children.

It’s that scandalous behavior that eventually leads to a break between the two men, although earlier disagreement over Freud’s insistence on a sexual element in all neurosis has already tested the physicians’ collegiality. The distance between them increases when, during a joint voyage to the United States, Jung not only takes a first-class cabin that separates him from the older man but relates a dream that Freud interprets as a rejection of his authority. The rupture between them grows into what can be seen as an archetypal father-son battle.

It remains, however, a cerebral battle, especially for Freud, whom Mortensen plays with imperturbable reticence. Without doing much of anything in exterior terms, the actor effortlessly holds the screen every moment he’s on it, exuding the brooding charisma of a revered yet cunning pioneer. Fassbender is appropriately more the extrovert, especially in his scenes with Gadon: he understandably loosens up in those with Knightley, though even in the discreetly-composed moments in which Jung spanks Sabina to encourage sexual arousal, he conveys the man’s discomfort with such a display. Of the three stars, the most controversial performance is certainly Knightley’s, which is by far the most theatrical. Her hysterical fits in the first act are almost comically extravagant—though apparently very much in line with nineteenth-century clinical descriptions of such episodes—and her Russian accent is equally broad. But she grows more subtle as the film proceeds, and her relative flamboyance compared with her co-stars is a defensible choice, as to a certain extent she and Cassel (also playing more broadly) represent the unbridled id in comparison to the psychologist’ buttoned-down, civilized control.

That same control is evident in Cronenberg’s handling of the material. He maintains a steady, deliberate pace that inattentive viewers might mistake for lethargy. But though the surface of the picture is unfailingly elegant and attractive—with James McAteer’s production design, the art direction by Sebastian Soukop and Anja Fromm, Gernot Theondel’s set decoration and Denise Cronenberg’s costume design all impeccable in their attention to period detail, and cinematographer Peter Suschitzky capturing all their contributions (as well as the European locations) with cool effectiveness—a sensitive viewer will sense the turmoil constantly simmering beneath the apparently placid exterior. Howard Shore’s score, which—like Lars von Trier’s “Melacholia,” but to far greater point—incorporates a good deal of Wagner, contributes to the deceptively genteel mood the director has been at pains to create.

The result is a film that mirrors its title in being—like all of Cronenberg’s work—superbly methodical, but also captures the dangerous undercurrents implicit in the understanding of man that Freud and Jung were instrumental in creating.