> Also, what is "impaired cognition"? Compared to what, exactly?

How about this for an operational definition: When you open your eyes and are seeing shit that isn't there, you're suffering from impaired cognition.

It's really not that difficult, unless you want it to be.

Edit: OK Fine. I give up: It's mysterious cosmic stuff that puts you in touch with the everlasting oneness of all humans and the universe. Good luck with the whole enlightenment thing, I'm sure the chemicals will fast-track you to exactly the right path.