Its on the sheet but not in the core book,

Yes it is, page 280 is where it starts, which is the 3rd page on Insanity rules.

thanks, i could not see it in the index.

Yeah some of the stuff is hard to find, Game Indexes alot of times miss somethings. That has to be my biggest beef with some of the FFG books. Ross take note: work on the index for quick references, I have the GM Screen but a full write out from the book is sometimes helpful.