The film was severely cut and re-edited for its American release - those versions vary from 81 to 97 minutes. The original is barely recognizable so try to catch the full version.
Although once branded a video nasty the full-length 118 minute Director's Cut was passed fully uncut by the BBFC on the Visual Film video label in 1999.
Spanish DVD by Filmax under the title 'La Posesion' is uncut.
Available uncut on a double-sided Region 1 DVD from Anchor Bay. The uncut version is paired with Mario Bava's 'Schock' (also uncut)
While the Anchor Bay DVD from 2000 and the Second Sight Blu-Ray from 2013 feature the same cut of the film, the DVD has a lot more incidental music on the soundtrack, most notably repeated instances of the dramatic piano theme that appears during the end credits of both versions. The Blu-Ray, however, does feature loud and sinister ambient music during a pivotal scene near the end of the film that contains no music on the DVD.
The first USA version released in 1983 had heavy edits. As well as being around 40 minutes shorter than the original, certain scenes have music and/or optical effects added to give it more of a horror film feel.
The shortest version of Possession runs 80 minutes and was cuts in nearly every scene with a number of scenes being completely deleted, especially near the end. Several scenes were also moved to another location. Anna's ballet lesson and Mark's report to his superiors were used as a pre-credits sequence. Anna's miscarriage in the subway tunnel appeared before Mark visited Heinrich and Mark's first encounter with Helen appeared after he sat on the bed by Margit. The film's climax was rendered incomprehensible by the heavy use of filters and editing. The film also featured a new soundtrack, composed by Art Philips (III), playing up the horror aspect of the film featuring a children's choir rendition of "Baa Baa Black Sheep" and other themes featuring distorted voices and synths.