According to Debbie Reynolds, Shelley Winters' psychiatrist advised her not to portray a woman having a nervous breakdown because, at the time, she was actually having a nervous breakdown. "She's the kind of actress who becomes the part she's playing..." said Reynolds, "so all through the film she drove all of us insane!"
Debbie Reynolds drove Shelley Winters to work each day. One morning on her way to pick up Shelley, Debbie noticed a woman standing on Santa Monica Boulevard in a nightgown trying to flag down a ride. When Reynolds stopped and asked why she was not waiting at home, Winters replied, "I thought I was late."
When friend/director Curtis Harrington offered her the part, Shelley Winters took the lead role in the film without even reading the script.
As part of the contract for her short-lived self-titled TV sitcom, Debbie Reynolds had a deal with NBC to produce a film, and she loved Henry Farrell's story outline, as well as the notion of taking a dramatic role in a horror film. NBC put up $750,000 and Reynolds invested $800,000 of her own, producing the film uncredited.
Bit player Yvette Vickers was instructed to dye her blonde hair red, so as not to compete onscreen with blonde star Debbie Reynolds.