The sound is NOT teeth grinding

[onewolf]

The sound is probably just meant to be unnerving, like nails on a chalkboard or something like that

Also, when you hear it you know that your sanity is decreasing.

That's true, and I don't mind the sound per se. I do find that what it eventually sounded like to me is a poor representation of teethgrinding, and I couldn't shake that impression. I like the concept, but that particular sound and more specifically the volume at which it is played to be distracting rather than contributing to the otherwise immersive cache of excellent sound effects.