Il gabinetto del dottor Caligari

Writer Hans Janowitz claims to have gotten the idea for the film when he was at a carnival one day. He saw a strange man lurking in the shadows. The next day he heard that a girl was brutally murdered there. He went to the funeral and saw the same man lurking around. He had no proof that the strange man was the murderer, but he fleshed the whole idea out into his film.

In the wide shot, the sign at the asylum reads "Insane Asylum," in English. In the close-up, the sign is written in German (Kino Blu-ray Disc version, may not be present in all editions of the film).

USA laserdisc reissue restores the original hand-drawn title cards that have been missing from every known print of the film since 1923. When first released on video in the United States, film was in black-and-white, and played back many scenes at double speed and featured different music. Although no scenes were cut out, the running time was reduced to only 51 minutes. The restored version restores the colour-tinting, restores the original title cards, and plays the film back at regular speed, returning the film to its original 69-minute running time.

Edited into People Who Die Mysteriously in Their Sleep (2004)