Dementia 13 was one of several Roger Corman productions veteran B-movie character actor Campbell appeared in, but it was the first that was completed on such a small budget. Coppola had convinced Campbell (and his The Young Racers co-star Patrick Magee) to appear in the film. The actor originally felt that it would turn out to be a strictly "amateur endeavor", but he soon became impressed by Coppola's leadership abilities, talent, and energy on the set. Campbell recalled years later, "There were all kinds of promises as to what he [Coppola] would do for me later. It was one of those 'I-owe-you-one' things, but he never did anything! I tried to get to him when he was doing The Godfather, thinking that a cop or gangster part might be good for about 17 weeks, but after Dementia 13, I was never able to get through to him again!" Anders' role as the scheming wife of a rich but prematurely dead heir to a fortune is one of the actress's most notable screen roles. Dementia 13 was one of several appearances that she made in AIP productions. Most of these films had been directed by Roger Corman, including a major role co-starring with Vincent Price in The Pit and the Pendulum (1961). Like Campbell and Patrick Magee, Anders had been borrowed by Coppola from the cast of Corman's just-completed film The Young Racers. After Dementia 13, Anders never had such a sizable role again, appearing in numerous small parts in both television and film until her death from breast cancer in 1996. Magee's role as the family doctor who manages to solve the mystery in Dementia 13 was one of many horror film parts the Tony Award-winning actor accepted during the course of his distinguished career. He had just finished shooting Corman's The Young Racers when Coppola convinced him, along with his Racers co-stars Campbell and Anders, to appear in Coppola's debut feature. Years later, Campbell warmly remembered Magee as being a brilliant performer although a little prone to overacting. Filming Principal photography on Dementia 13 began on September 10, 1962 at Ardmore Studios in Bray, Ireland, under the working title "Dementia". During filming, Coppola kept Corman updated on the status of the production in letters that promised much sex and violence would appear in the film, "enough to make people sick". Coppola was left entirely on his own while directing