Trivia

Francis Ford Coppola was assisting Roger Corman on the set of The Young Racers (1963) in Ireland. Corman allowed Coppola to use the same set, crew, and actors Luana Anders, William Campbell, and Patrick Magee for this film if he could shoot around the shooting schedule of Corman's film.

American International Pictures would frequently make use of frozen dollars and cheaper European facilities by sending composers Les Baxter and Ronald Stein to record their scores in London, Munich, and Rome. In spite of The Terror (1963) having a very small budget, Stein was able to use the 90-piece Munich Symphony Orchestra to record the score for that movie. Furthermore, whilst in Munich, Stein cut costs even further by juggling the recording sessions to squeeze in the scoring of Dementia 13.

Francis Ford Coppola's first director credit, as "Francis Coppola".

The lyric in Tom Petty's song "American Girl" that goes "raised on promises" appears to have come from a line of dialogue in this film. Referring to another woman, Louise states, "Especially an American girl. You can tell she was raised on promises."

Director Francis Ford Coppola met his wife Eleanor Coppola during the making of the film.