To say that Michael Fassbender has been busy in the past 12 months is something of an understatement. The good news for the German-born Kerryman is that the numerous roles he has taken on have been about as varied as they come. We've seen him as a sex addict (Shame), a hit man (Haywire), a brooding Victorian (Jane Eyre), and a malevolent Mutant (X-Men: First Class), while the watercooler moment in this latest drama sees him put Keira Knightley across his knee and give her a vigorous spanking.

But more of that anon.

Based on John Kerr's 1994 book about the birth of psychoanalysis, A Dangerous Method is adapted from his own play, The Talking Cure, by the celebrated scribe, Christopher Hampton. The story of the burgeoning relationship between Sigmund Freud (Mortensen) and Carl Jung (Fassbender), the founding fathers of modern psychology, the movie seems an unusual choice of material for Cronenberg, who has made his name with his imaginative narrative choices and striking visuals.

In this case, the award-winning Canadian director has taken a restrained, intellectual approach to his subject matter. The movie opens in 1904 with the arrival of young Russian patient, Sabina Spielrein (Knightley) to Jung's Burgholzli Clinic in Zurich. Spielrein would later become a patient of Freud and eventually become a qualified colleague of both men. After some early consultations in which he tries out the ''talking cure'', Jung is convinced that Sabina's hysterical condition is linked to the fact that she was beaten by her father as a child and somehow developed a sexual response to this early trauma.

Sabina becomes a key link between the two studious men as they analyse, criticise and debate their respective positions within the world of psychoanalysis. Their professional relationship particularly takes a hit when Jung crosses the boundaries of patient/doctor relationship by becoming a little too hands-on with Sabina for his own good.

Though Knightley's character dominates much of the action (and most of the film's poster space), hers is the least interesting performance of the three. Apparently the English actress decided with Cronenberg that her character's hysteria should manifest itself in a dog-like fashion, with the actress uncomfortably jutting out her chin when in the throes of her psychosis. That might have worked well on paper but on screen it's a remarkably distracting and un-affecting approach.

Mortensen fares better as the cool, analytical, cigar-chomping Freud, entertaining his young Swiss admirer (a man he once called his son and heir) and enjoying the intellectual jousting between the two. Fassbender also seems to relish the wordy battles with his Viennese counterpart, having the skill and the experience to understand what's at the heart of Cronenberg's theatrical approach to his story.

Overall, though, A Dangerous Method is a dramatically un-involving experience.

Michael Doherty