Mentally ill people are not a sideshow of monsters and freaks
I'm so sick and tired of seeing distorted caricatures of mentally ill individuals next to vampires and werewolves in the horror movie section. Mental illness is a debilitating and often fatal health issue that is only rendered more socially crippling by media stigmatization in general and the "scary crazy people" horror movie trope in particular.
Some might consider this post to be a spoiler, but the plot summary / press release blurb of this unimaginative concoction, which falsely describes agoraphobia as a psychosis and shows how little background knowledge went into the script, already gives the basic plot away: Home invaders turn from hunters to hunted because mentally ill people are oh so dangerous and violent. Feh.
If you don't understand why the utter lack of creativity that compels writers and directors to turn a disenfranchised and much-stereotyped minority into movie villains is a social issue, just imagine a horror flick that shows Jewish people sacrificing Christian children on Passover. This movie is just as unacceptable, and for exactly the same reason. (In case you don't know what I'm talking about, I suggest you google "Aktion T4").
Bottom line: Unlike fangs, horns and claws, mental illness is not an acceptable movie monster attribute. Mentally ill individuals have enough crap to deal with and really don't need this undeserved stigma and misinformation. It shouldn't be that difficult to come up with a creative and original horror movie monster/villain who isn't based on a minority demographic.