This is, without a doubt, a broad question with many possible answers. Every horror fan (or movie fan for that matter) will have their own opinion in regards to what makes a movie truly disturbing.
I posted this question to social media as well as a group of my horror loving friends and while they had varying opinions over what movies are disturbing, their answers in what makes them terrified were basically the same; Realism.
To quote one friend, “Once a genuine fear is played upon in a realistic setting, then that makes a movie truly disturbing.” Another person stated that we are all affected by different things so it’s the things that gets under your skin that are played upon to create the terrifying effect, for example phobias or belief systems.
Believability is the key.
A lot of people also agree that music combined with the building of tension and atmosphere also add to the creep factor. “A singular piano key strike as the tension builds is enough to send a well deserved chill down my spine. John Carpenter did this perfectly with the Halloween score.”
I have to say, I agree with realism being the key to making a film disturbing. And a film is only disturbing to you if it stays with you long after you’ve seen it. Movies that play on genuine fear and express something that could actually happen are the movies with the biggest impact on the human psyche.
For example, Last House On The Left (the original) disturbed me way more than Saw. The probability of being kidnapped, tortured, raped and murdered is vastly higher than being kidnapped, drugged and suspended in a death trap for which you have to prove your will to survive in order to “win” the game. I’m not saying something like the Saw series couldn’t happen, I’m just saying it’s highly unlikely.
Jaws is another perfect example of believability taking a hold of the mass and evoking hysteria. Jaws, even to this day, has kept people out of the ocean. Hell, it kept me out of my bathtub when I was a kid. It played on the fear of being attacked and eaten by something lurking just below the surface.
It’s not always the entire film that gets people talking. When this question was posted to my horror group, one young lady stated that the scene in the Texas Chainsaw Massacre where Sally was screaming whilst sitting at the dining table had her disturbed. It wasn’t the screaming from Sally that unnerved her, it was the fact that her captors screamed along with her, getting louder each scream before finally bursting into maniacal laughter.
When it comes to disturbing moments, every horror movie has one but it depends on the severity level of your desensitization as to how much of it you will indeed find disturbing. If you’re like me and just yawn when blood pours out of an open wound, then maybe a little jump music in Urban Legends won’t set you running for the hills. If you’re like my mother and have seen Halloween a million and one times and you know every aspect of the movie but still jump in the same part, then you may find other movies in a similar category enjoyable, but not disturbing.
Upping the intensity level of horror is the ultimate goal to most film directors and writers. And while that works on a vomit-inducing scale, it doesn’t always work for savvy modern day horror enthusiasts. There has to be a sense of “This could happen to me” otherwise the movie will simply be that; a movie.
In order for a movie to leap off the screen and affect people, the audience has to live it. They have to be draw into the story, the characters and the setting. They have to believe what is happening before them. Without that believability then there’s nothing truly disturbing.