David Cronenberg’s new film, “A Dangerous Method,” opens in 1904 with a young woman, Sabina Spielrein, hysterically banging her face against a carriage window. Moments later she is dragged screaming from the carriage and hauled into the Burgholzli Clinic in Zurich, Switzerland, where she is to be treated by Dr. Carl Jung. Yes, that Carl Jung (Michael Fassbender in a perfectly shaped performance.)

Keira Knightley is here to give us Sabina Spielrein, a tortured and withered young Russian Jewish student who will one day, despite her overwhelming and frightening problems, become a well-known Freudian-trained psychoanalyst on her own, before she falls headlong into the madding vortex of the 20th Century and the rise of Nazism.

“A Dangerous Method,” based on Christopher Hampton’s play “The Talking Cure,” and John Kerr’s 1993 “A Most Dangerous Method,” is at its heart, a tangled love story of sorts, perhaps between the two brilliant men, both with immense egos, and Sabina, whose work they both reportedly appropriated in their later work.

The film centers on the well-known relationship between two of the greatest minds of their time, Carl Jung and Sigmund Freud. I must admit that I have forgotten all of my schoolboy memories of that fabled relationship, and regrettably lost all of the notes I compiled on my treatise on psychotherapy. Father Kelleher and the good Sisters of Saints Mary and Joseph rarely touched on the problems of lust, hysteria and sexual repression that Dr. Freud explored.

What I have learned here is that Jung believed Freud was overboard on his idea that sexuality was a motivating force in all things. Even though I rush to agree with this theory, (Thank you Rosemary De Branco and Joya Feldburg) I hesitate to expound on it at length here, in fear that I might seem elitist and accidentally expose my ignorance of the subject.

You and I, dear viewer, caught up in daily problems as we are, have probably forgotten much about this relationship. Cronenberg and his writers work hard here to refocus us.

Let’s first talk about the salient issues. The film itself is lovingly put together with great costumes, a smart script, albeit teetering a bit on the edge of pedantic, and attention to detail like Freud’s iconic cigar (“sometimes a cigar is just a cigar.”) We should add that praise must be given to Gernot Thondel’s sets, Denise Cronenberg’s costume design and Peter Suschitzky’s cinematography.

Of the cast, we can’t say enough about the work of Fassbender. His Carl Jung is richly detailed and most of what keeps the film from becoming tedious and didactic is because of Fassbender. It’s impossible not to notice as well, the too brief contribution of the great French actor Vincent Cassel as a psychiatrist/patient, who opens a door for Jung that would have best been kept closed. Cassel is always brilliant.

Viggo Mortenson, usually an action figure, as Sigmund Freud, is interesting to watch. He does all sorts of little things with his cigar, his pens and paper, watch fob and silver-headed cane. In film acting this is called “playing the props.” Cronenberg, a director I’m fond of and who is known lovingly as ” The Baron of Blood,” used Viggo best in “A History of Violence, and “Eastern Promises,” movies I truly liked. But roles like this are usually better left in the hands of actors such as Max Von Sydow.

And then there is Knightley. I’m not a big fan of her work, and she did nothing here to win me over. Her portrayal of Sabina Spielrein was so overboard as to make me wince. She clearly did her research, but the popping eyes and twitching, gnarled fingers brought back fond memories of the evil queen in “Snow White” when the mirror gave her the bad news. I’m sure it was historically accurate, it’s just watching Knightley do it that turned me off.

A note for the faint of heart: The twisty love affair between Jung and Sabina gives the film its perky and erotic upbeat moments when they enjoy the simple pleasures of those togetherness moments as she reached orgasmic heights with Dr. Jung manning the whipping stick. Oh my.

Sarah Gadon as Jung’s “extremely wealthy” wife Emma, lends a poetic tenderness to her scenes as she struggles to maintain her dignity when the scandal floats to the surface. Gadon has that elusive quality they call haunting. It will serve her well.

“A Dangerous Method” is what is known as an important film. I leave it at that.

J.P. Devine is a former stage and screen actor.