When the cast and crew began work on the first day, they had to raise their right hands and promise not to divulge one word of the story. Alfred Hitchcock also withheld the ending part of the script from his cast until he needed to shoot it.
Director Sir Alfred Hitchcock was so pleased with the score written by Bernard Herrmann that he doubled the composer's salary to $34,501. Hitchcock later said, "Thirty-three percent of the effect of Psycho was due to the music." Ironically, he was originally adamant that there should be no music in the shower scene but he was persuaded by his wife to give it a try. The screeching violins and dire strings (which would inspire the music for Jaws (1975)) ending up selling the scene and driving theatrical audiences beyond anything they had ever experienced.
After this movie's release, Sir Alfred Hitchcock received an angry letter from the father of a girl who refused to have a bath after seeing Diabolique (1955), and now refused to shower after seeing this movie. Hitchcock sent a note back simply saying, "Send her to the dry cleaners."
Director Sir Alfred Hitchcock bought the rights to the novel anonymously from Robert Bloch for only $9,000. He then bought up as many copies of the novel as he could, to keep the ending a secret.
Anthony Perkins and Janet Leigh said that they did not mind being stereotyped forever because of their participation in this movie. They said in interviews they would rather be stereotyped and be remembered forever for this classic movie than not be remembered at all.