Schizo is a 1976 British psychological horror slasher film directed and produced by Pete Walker and starring Lynne Frederick, John Leyton and Stephanie Beacham.
US poster (1977)
A slasher film is a subgenre of horror films involving a killer stalking and murdering a group of people, usually by use of bladed or sharp tools. Although the term "slasher" may occasionally be used informally as a generic term for any horror film involving murder, film analysts cite an established set of characteristics which set slasher films apart from other horror subgenres, such as monster movies, splatter films, supernatural and psychological horror films.
A scene from the Grand Guignol, a format some critics have cited as an influence on the slasher film
Dorothy McGuire in The Spiral Staircase (1946)
A scene from Mario Bava's A Bay of Blood (1971), which was notably imitated in Friday the 13th Part 2 (1981)