Ratings
Psycho has been rated and re-rated several times over the years by the MPAA. Upon its initial release, the film received a certificate stating that it was "Approved" (certificate #19564) under the simple pass/fail system of the Production Code in use at that time. Later, when the MPAA switched to a voluntary letter ratings system in 1968, Psycho was one of a number of high-profile motion pictures to be retro-rated with an "M" (Mature Audiences). This remained the only rating the film would receive for 16 years, and according to the guidelines of the time "M" was the equivalent of a "PG" rating. Then, in 1984, during the uproar of increased parental concern regarding violence in "PG" films, Psycho was retro-rated again to its current rating of "R." This rating took effect, however, before the institution of the "PG-13" rating by the MPAA that same year, and there are those who have speculated that if the rating had existed at the time, or if Psycho were rated in America today, it would receive a "PG-13."
Read more about this topic: Psycho (film)