Sdrolion said:
Like Julia said, you can use it and go insane, but keep in mind that when you go insane you lose half your clue tokens (rounded down)...pretty sure that would include the ones you just got for using the item.
Yeah, unless you choose to instead get a Madness card from the Dunwich expansion.
Edit: Actually, come to think of it, this may be a houserule we're using: It makes sense to us that since you don't lose any items, you also don't lose any clue markers. It's not really stated anywhere, though, IIRC.