Viggo Mortensen. David Cronenberg. Michael Fassbender.
Three very good reasons to put this on your must-see list. But if you need more, it also stars Keira Knightley & Vincent Cassell and concerns the friendship and psychological constructs of Carl Jung (Fassbender) & Sigmund Freud (Mortensen). And Jung's exploration of his methods through an affair with one of his patients (Knightley).
Cronenberg is never light watching, but he is on a career high. His last two films with Mortensen (A History of Violence, Eastern Promises) were powerful, violent and intensely constructed films, so tackling a period romantic psychological drama is an intriguing next move. Knightley seems on the borderline of overacting, but I doubt that Cronenberg would allow that, so it should be a good vehicle for her.