Dementia 13 is a 1963 horror thriller released by American International Pictures, starring William Campbell, Patrick Magee, and Luana Anders. The film was written and directed by Francis Ford Coppola and produced by Roger Corman. Although Coppola had been involved in at least two nudie films previously, Dementia 13 served as his first mainstream, "legitimate" directorial effort. The plot follows a scheming young woman who, after having inadvertently caused the heart attack death of her husband, attempts to have herself written into her rich mother-in-law's will. She pays a surprise visit to her late husband's family castle in Ireland, but her plans become permanently interrupted by an axe-wielding lunatic who begins to stalk and murderously hack away at members of the family.
Corman offered Coppola the chance to direct a low-budget horror movie in Ireland with funds left over from Corman's recently completed The Young Racers, on which Coppola had worked as a sound technician. The producer wanted a cheap Psycho-copy, complete with gothic atmosphere and brutal killings, and Coppola quickly wrote a screenplay in accordance with Corman's requirements. Although he was given total directorial freedom during production, Coppola found himself fighting with Corman after the film was completed. The producer declared the movie unreleasable and demanded several changes be made. Corman eventually brought in another director, Jack Hill, to film additional sequences.
Upon arrival, she immediately notices that things are a little strange in the castle. She observes John's two brothers, Billy (Bart Patton) and Richard (William Campbell) taking part in a bizarre ceremony with their mother as part of a yearly ritualistic tribute to their youngest sister, Kathleen, who died many years before in a freak drowning accident. Lady Haloran still mourns for her, and during this year's ceremony, she faints dead away. As Louise helps her into the house, her mother-in-law tells her that she fainted because one of the flowers she had thrown had died as it touched Kathleen's grave.
Louise, realizing that Lady Haloran is emotionally overwrought and superstitious, devises a plan intended to convince the old woman that Kathleen is trying to communicate with her from beyond the grave. This plan involves stealing some of the dead girl's old toys and placing them at the bottom of the estate's pond where they will float to the surface in the middle of the day in an ostensibly ghostly way. At night, Louise swims into the pond and begins placing the toys as planned. However, she is shocked to see what appears to be Kathleen's perfectly preserved corpse at the bottom of the pond. Horrified, she swims to the surface... and is abruptly axed to death by an unknown assailant. The killer then drags Louise's bloody corpse away.
Concerned family doctor Justin Caleb (Patrick Magee) arrives and becomes determined to solve the mystery. He questions the family in an intense, almost insane manner. Caleb has the pond drained, revealing a stone shrine for Kathleen, with the words "Forgive Me, Kathleen" on the monument. Meanwhile, the murderer strikes again, decapitating a man who is poaching on the estate. The following night, Lady Haloran is attacked by a shadowy figure, but she survives.
Finally, Dr. Caleb utilizes an obscure nursery rhyme ("Little fishies in a brook, papa's hanged you on a hook") to help him discover Louise's corpse hidden in a meat freezer. Next to the body is a wax figure of Kathleen. Caleb places the figure in a public square to lure the killer. Taking the bait, a gibbering Billy attempts to kill Richard's fiancée Kane (Mary Mitchel) with an axe; he has become insane with the guilt he has felt for years over having caused the death of his sister Kathleen. Dr. Caleb removes a gun from his coat pocket and shoots Billy to death.
Coppola wrote a brief draft story idea in one night. The next morning, he described to Corman the most vividly detailed sequence: a half naked woman ties several dolls to the bottom of a lake, then surfaces to find herself at the feet of an axe murderer -"Axed to death!" Coppola exclaimed." Corman was impressed enough to immediately provide Coppola with the $22,000 for the film. The young director was able to arrange an additional $20,000 in financing himself by pre-selling the European rights to a producer named Raymond Stross. Coppola did not inform Corman of the production's additional funding, and quickly moved the initial $22,000 into a bank account in case an angry Corman ever attempted to reclaim his original investment.
Coppola’s friend Al Locatelli served as the film’s art director and helped Coppola write the final script in three days, uncredited. The speed in which the screenplay was completed resulted in unrealistic, “stilted” dialogue that Campbell recalled as being very difficult for the actors to speak.
The majority of the American actors in the cast were friends of Coppola’s from UCLA, and many of them paid their own way to Ireland for the opportunity to appear in a film. Most of the Irish cast members were from the Abbey Theatre and were paid strictly minimum wage salaries. Eithne Dunne received approximately $600 for her performance. Cast and crew lived together in a farm house located outside of Dublin.
During the filming, Coppola kept Corman updated on the status of the production in letters that promised lots of sex and violence would be in the movie, "enough to make people sick".Coppola was left entirely on his own while directing the film, without interference of any kind from Corman. But after the completed film was shown to him, Corman stormed out of the screening room and demanded that several changes be made to the film that Coppola did not agree with. According to Coppola, Corman "insisted on dubbing the picture the way he wanted it, adding voiceovers to simplify some of the scenes. Worse, he wanted some extra violence added, another axe murder at least..." Jack Hill was later hired by Corman to shoot some brief sequences featuring actor Karl Schanzer as a comical poacher who is beheaded by the murderer.
Corman also complained the film was too short, and insisted that it be padded by at least five minutes. Gary Kurtz, one of Corman's assistants at the time, recalled, "So we shot this stupid prologue that had nothing to do with the rest of the movie. It was some guy who was supposed to be a psychiatrist, sitting in his office and giving the audience a test to see if they were mentally fit to see the picture. The movie was actually released with that prologue." The prologue was directed by Monte Hellman. This cheap William Castle-style gimmick also included a "D-13 Test" handout given to theatre patrons that was ostensibly devised by a "medical expert" to weed out psychologically unfit people from viewing the film. The test consisted of such questions as "The most effective way of settling a dispute is with one quick stroke of an axe to your adversary's head?" and "Have you ever been hospitalized in a locked mental ward, sanitarium, rest home or other facility for the treatment of mental illness?", with Yes or No as the only possible answers.
When the Roan Group released a laserdisc and DVD of the film, it included an amusing and informative audio commentary by Campbell. The DVD also featured the written version of the "D-13 Test" in digital form as an extra. However, the filmed five-minute prologue featuring the test has not been included on any of the numerous available home video versions of the title.