Has any North American filmmaker led us further into the labyrinths of the human psyche than David Cronenberg? Since making his name in the early 80s with a trio of bizarre horror movies—Scanners (1981), Videodrome (1983), The Fly (1986)—the Canadian writer-director has ventured into progressively more challenging psychological territory, exploring narcotics addiction (Naked Lunch), the sex-death instinct (Crash), the treacherous workings of memory (Spider), and our appetite for carnage (A History of Violence). Given that track record, the source material for his latest drama might seem like an ideal property: John Kerr’s 1993 nonfiction book A Most Dangerous Method, about the scintillating but ultimately fractious professional friendship between Carl Jung and Sigmund Freud. For a filmmaker so curious about the mechanisms of the mind, what better project could there be than a biopic about the two great founders of psychoanalysis?

A Dangerous Method, which opens Friday at Landmark’s Century Centre and Century 12/CineArts 6, never really delivers on that promise, mainly because its scenes of two brilliant men discussing the nature of the subconscious can’t compare with Cronenberg’s visual rendering of that subconscious in earlier movies. Certainly there’s some juicy stuff here: the story revolves around Jung’s tempestuous relationship with Sabina Spielrein, a deeply troubled young medical student who began as his patient, became his mistress, blackmailed him into referring her to Freud as a patient, and ultimately distinguished herself as a psychoanalytic theorist of some note. But in the movie this leads to an odd dichotomy between the drily cerebral and the powerfully sexual: on the one hand, decorous scenes of intellectual jousting between the two esteemed gentlemen, and on the other, primal shots of Jung (Michael Fassbender) and Spielrein (Keira Knightley) getting it on, which culminate in a bound Spielrein shouting with pleasure as Jung spanks her with a leather belt. (Regardless of the rating above, I give this scene four stars, an A+, and two thumbs up.)

I haven’t seen the Christopher Hampton play that was Cronenberg’s more direct source material, but somewhere between the book and the movie, much of the intellectual subtext that makes the story of Freud and Jung so engrossing has slipped away. A Most Dangerous Method is long, dense, and clinical, but it masterfully conjures up the academic tumult of the early 20th century, which nurtured and then poisoned the friendship between Jung and Freud. Based in Vienna, Freud had pioneered the study of psychoanalysis with his 1899 book The Interpretation of Dreams; one of his most ardent disciples was Jung, who had begun to apply Freud’s ideas about repressed sexual trauma to his treatment of patients at the Burgholzli Psychiatric Clinic in Zurich. For Freud, whose concept of human sexuality scandalized Victorian society, Jung was a welcome ally, a young and clearly brilliant physician whose access to the clinic might permit the sort of empirical research Freud desperately needed to advance his work.

Without this social and theoretical background, one might not fully appreciate how threatened Freud must have felt by Jung’s affair with a patient. Had it become public knowledge, it might have destroyed not only Jung’s professional reputation but the very practice of psychoanalysis, which dwelled on the most intimate matters and often caused the patient to transfer to his therapist emotion he once felt for someone in his past. The last thing the psychoanalytic movement needed was for polite society or the academic world to decide “the talking cure” was some sort of sexual con. Kerr reconstructs the whole mess as best he can from the surviving correspondence between Jung, Freud, and Spielrein. Much of the story remains obscure, but it’s clear that Spielrein, enraged after Jung broke off the affair, ratted him out in a long letter to Freud, and that Jung first lied to protect himself but eventually confessed to his beloved mentor. What finally severed the bond between Freud and Jung, though, was not the affair but Jung’s growing interest in spiritualism, which Freud regarded as an even graver threat to psychoanalytic practice.

The convoluted intellectual politics of Zurich and Vienna having been discarded, A Dangerous Method functions less as a social history than as a philosophical drama, centered on Jung and using other characters as embodiments of a single idea. (This design makes more sense if we remember that psychology had its roots not in medicine but in philosophy.) The opening scenes show the virile young physician enjoying a settled home life with his beautiful and doting wife, Emma (Sarah Gadon), whose successive pregnancies have put a damper on their sex life. His adoring friendship with Freud (Viggo Mortensen) takes on the contours of a father-son relationship and, as Jung outgrows the older man’s strict doctrine, the very Oedipal complex that Freud proposed as the core of human psychology. Spielrein represents the self-destructive urge that she herself would later examine as a writer, inspiring Freud’s idea of the death instinct. Last but not least, there’s the dissolute psychoanalyst Otto Gross (Vincent Cassel), who preaches personal freedom above all else and urges Jung to accept Spielrein’s sexual advances.

Some reviewers have faulted Knightley for her over-the-top performance as Spielrein, but thank God there’s someone on hand to upset the teacups. The movie opens with Spielrein shrieking and laughing hysterically as she’s delivered by carriage to the Burgholzli clinic, and in her first session with Jung her nervous spasms are so intense she looks as if she’s going to dislocate her jaw. Under Jung’s questioning, she eventually reveals that as a girl she was powerfully aroused by her father’s habitual spankings. When Jung picks up her dropped coat during a stroll on the clinic grounds and beats it with his walking stick, Spielrein is so turned on that she has to excuse herself. “I want you to be ferocious,” she tells him during one of their secret meetings. “I want you to punish me.” Jung knows full well the affair might destroy his marriage and his career, but he pursues it anyway; perhaps, as Spielrein would have it, he actually craves the damage. Jung phrases it beautifully in what turns out to be the movie’s final line: “Sometimes you have to do something unforgivable just to be able to go on living.”

The devil on his shoulder is undoubtedly Gross, who shows up at the Burgholzli clinic for treatment but proves so insightful that Jung begins to wonder whether he’s the therapist or the patient. The son of a Munich judge, Otto Gross embraced Freud’s idea that repression was the cause of all neuroses, and no one could accuse him of denying himself. He was addicted to cocaine and morphine, and a series of sex scandals, including a rumored affair with a patient who ultimately killed herself, prompted his father to have him committed. “Not to repress yourself is to unleash all kinds of dangerous and destructive forces,” Jung tells Gross, but Gross will have none of this. “Our job is to make our patients capable of freedom,” he replies. When Jung confesses that Spielrein has propositioned him but he hasn’t responded, Gross is incredulous: “I can’t understand what you’re waiting for. Just take her to some secluded spot and thrash her to within an inch of her life. That’s clearly what she wants.” Eventually Gross boffs one of the nurses at the clinic and climbs over the wall, leaving Jung a note that reads, “Do not pass by the oasis without stopping to drink.”

If Gross is the rebellious brother Jung envies, Freud is the forbidding father he both loves and fears. Jung’s letters to Freud were filled with the most hyperbolic expressions of devotion; he likened his feelings toward the good doctor as a “religious crush.” In turn, Freud saw Jung as a healthy, strapping young son who could take over the reins of the psychoanalytic school when the time came (and, no less important, a Gentile who could circumnavigate the sort of anti-Semitism afflicting the movement in Vienna). But the tension between them grew as Jung, in his published writings, tried to enlarge the scope of psychoanalytic theory beyond sexuality and into the spiritual realm, to transform it into a genuine worldview. In the movie, this Oedipal clash comes to a head during a meeting of the International Psychoanalytic Congress, when Jung and Freud, seated at opposite ends of a table, debate the link between monotheism and patricide. Freud petulantly notes that Jung failed to mention him in his last paper, and after Jung decisively corrects him on an arcane historical point, Freud gets up to leave, grows faint, and keels over backward.

Despite all these grand concepts bouncing around, A Dangerous Method settles at the level of a male tearjerker, with Jung begging Spielrein not to move away to Vienna and study under Freud. “You were the jewel of great price,” he tells her. One wonders what happened to the David Cronenberg who crafted such arresting, nightmarish imagery in his earlier movies. Jung himself may have written the perfect review of A Dangerous Method in 1910 when he explained his ideas about symbolism in a letter to Freud. “‘Logical’ thinking is thinking in words, which like discourse is directed outwards,” Jung wrote. “‘Analogical’ or fantasy thinking is emotionally toned, pictorial and wordless.” A Dangerous Method could have used more of the latter. For psychoanalytic patients, talking may provide a cure, but for the cinema in general and this movie in particular, it’s more like the disease.