The Return of The Repressed

The Return of The Repressed. 

Is a theory by Sigmund Freud which stated that human beings who have been subject to mistreatment and torment at a young age can bottle up in the unconscious mind and then spill out at a later point in life. This is often seen in horror films where antagonists can seem relatively normal up until their feelings that have been repressed are unleashed turning them into a monster.