Freud had come up with the idea of “the talking cure” but had never actually tried it on a patient. When Jung does, and succeeds in bringing Spielrein’s mania under control enough for her to begin medical school herself, the two men become colleagues and friends. Meanwhile, the sexual nature of Spielrein’s symptoms and obsessions, Jung’s colorless marriage to wealthy Emma (Sarah Gadon), and the perverse influence on Jung of pure-id patient Otto Gross (a delightful Vincent Cassel, stealing every scene he’s in) push Jung and Spielrein toward an intense affair. (Being veddy proper Europeans of their era, they couple half-clothed, although her masochism means a steady diet of enthusiastic flogging.) In this telling—Christopher Hampton based the screenplay on his own play, which was based on John Kerr’s nonfiction account—Jung’s relationship with Spielrein precipitates the differences and disagreements lurking beneath Jung and Freud’s professional and personal relationship, leading to a dramatic split from which their bond never recovered and, in many ways, from which psychology itself is still healing.