20 Movies That Could've Been Horror Movies

13. Requiem for a Dream

Requiem for a Dream is one of the most powerful depictions of addiction in cinema history, and that's in large part because Aronofsky basically shoots and structures it like a heightened horror film.

The filmmaker does a masterful job of depicting addiction in various forms - to heroin, diet pills, and even fame - as an all-encompassing, all-consuming entity which devours anything it encounters.

Though technically a psychological drama, as an audio-visual experience pretty much everything about Requiem for a Dream is horror-coded, from Matthew Libatique's deeply uneasy visuals to Clint Mansell's discordant musical score and, of course, the performances - especially Ellen Burstyn's haunting, Oscar-nominated turn.

While "elevated horror" films are often criticised these days for their obvious, transparent allegories, Aronofsky was totally ahead of the curve here by injecting a seemingly familiar addiction drama with a dizzying, anxiety-inducing style far more appropriate for a horror movie.

Like any truly rattling horror film, this is a ride you probably won't want to take too often.