**Beware Los Spoilers**
Many horror film theories are in reaction to gender and how could they not be? Men and women are constantly set against each other and their actions and outcomes. A lone male attacker terrorizing a group of young women until one woman is resourceful enough to fight back is a common horror plot. It is a rare occasion where the woman is the attacker (see Friday the 13th Part1, Misery, Haute Tension) but when the woman is the attacker she must have a clear and direct motive no matter how inconsequential it may seem to the rest of the characters.
Two prominent horror films release in the last two years have dealt with the notion of the female psyche inflicting itself on the world around them with disastrous results for the main characters. In Black Swan (2010) Nina Sayers (Natalie Portman) deals with her rising star as her eating disorder overtakes her. Black Swan is explicitly about an eating disorder as the theme is introduced to the audience in the first five minutes of the film. Nina in particular is a tragic figure as her eating disorder is so apparent yet no one does or says anything. It is shown but never talked about.