Insanity areas?

[Equil]

What do these areas do? Do they automatically apply sanity damage slowly while the player is inside one? I made one on my test map and stood inside it for a good 5 minutes without it effecting my sanity the slightest, so I looked at some of the official maps(mainly the storage map) to see how they used them.

I looked through the script for the storage map and found no functions/callbacks referring to any of these areas. Can anyone shed some light on this? Their purpose is probably painfully obvious and I've just missed something.